Caterpillartrack-type tractor
Caterpillar D4D
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar D4D is a small-class track-type tractor Caterpillar built from about 1963 into the late 1970s, one generation in the long-running D4 dozer line that traces back to the late 1930s. Early production ran the Cat D330 four-cylinder diesel at around 65 hp (48 kW); a bore and displacement increase around 1972 lifted output to roughly 74-75 hp (55-56 kW), and the engine was redesignated the 3304 under Caterpillar's new numbering scheme, though it remained the same mechanically governed, naturally aspirated block. Operating weight varies widely by configuration: a bare tractor with no blade runs about 5,900-6,900 kg (13,000-15,200 lb), a standard blade-equipped machine about 8,200-9,400 kg (18,000-20,800 lb), and heavier counterweighted or guarded agricultural builds reach roughly 10,900 kg (24,000 lb) without a blade. Caterpillar offered the D4D with either a 5-speed direct-drive transmission (flywheel clutch and bevel-gear steering clutches) or a 3-speed power-shift transmission built around a torque-divider/converter, plus straight (S) and angling (A) dozer blade options. The D4D replaced Caterpillar's earlier D4-series crawler tractor and was itself succeeded by the D4E.
Within its own run, the D4D's biggest change was under the hood: the D330 engine's bore-and-displacement increase and 3304 redesignation partway through production, which raised power without changing the tractor's basic footprint or undercarriage. The line split further by transmission — direct-drive and power-shift versions use different steering hardware and wear differently in the field — and by application, with heavier-duty agricultural and guarded builds alongside the standard dozer configuration. None of these variants carry any electronics: every gauge is analog, every fault shows up as a needle swing rather than a code, and diagnosis runs on compression checks, oil samples, and stall tests instead of a scan tool. That simplicity is exactly why the D4D still moves in the used-equipment and parts market today — it is inexpensive to buy, small enough for farm, ranch, and light grading work where a modern dozer is overkill, and serviceable by anyone comfortable with a wrench. Steering clutches, brake bands, cylinder heads, and undercarriage wear parts are well-understood failure points, and an active collector and rebuild community keeps knowledge and used parts circulating for this model.
Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.
Caterpillar D4D specifications
Engine
| Engine family / production run | Cat D330 four-cylinder diesel from the start of the run (about 1963); engines from roughly 1972 onward carry the Cat 3304 designation under Caterpillar's post-1972 engine-numbering change. Same base 4-cylinder architecture across the production life, which ran into the late 1970s. |
| Displacement, bore x stroke | About 7.0 L (425 cu in) on the higher-output engine; bore x stroke 121 x 152 mm (4.75 x 6.00 in). Earlier pre-1972 engines used a smaller bore and lower displacement, about 5.7 L equivalent. |
| Gross power | 65 hp (48 kW) on early production. Increased to about 74-75 hp (55-56 kW) after a bore and displacement increase around 1972, carried through to the end of the model run. Treat as a range across serial-number breaks, not a single fixed figure. |
| Rated engine speed | 1900 rpm on direct-drive tractors; 2000 rpm on power-shift tractors. |
| Drawbar / belt power (factory test rating, early engine) | Drawbar output about 52-68 hp (39-51 kW); belt output about 59 hp (44 kW). Figures vary by configuration and are closer to farm-tractor test convention than a dozer duty rating. |
| Aspiration and fuel system | Naturally aspirated, no turbocharger. Mechanical (sleeve-metering) fuel injection with mechanical governor, 12V or 24V electric start depending on configuration. |
| Emissions | Predates emissions certification requirements; mechanically governed diesel, no aftertreatment. |
Weights
| Bare tractor weight (no blade) | About 5,900-6,900 kg (13,000-15,200 lb) without blade or attachments, varies by production year and electrical/ROPS options. |
| Operating weight with standard blade | About 8,200-9,400 kg (18,000-20,800 lb) as equipped with a standard dozer blade and ROPS. Varies by blade type, gauge (Standard vs LGP), and factory options -- treat as a configuration-dependent range, not a fixed figure. |
| Heavier counterweighted configuration | Special counterweighted/guarded builds (radiator and belly guards for agricultural or forestry duty) recorded up to about 10,900 kg (24,000 lb) without blade fitted. |
Dimensions
| Overall length | About 3.9-4.4 m (13-14.5 ft) as equipped with blade. Varies with blade type and whether a winch or logging arch is fitted. |
| Overall width | About 1.9-3.0 m (6.3-10 ft) over tracks or blade. Narrower on Standard gauge, wider on LGP gauge or with a full-width blade fitted. |
| Overall height | About 2.4-2.7 m (7.9-8.9 ft) to the top of the ROPS canopy or exhaust stack, varies by canopy/cab option fitted. |
| Track shoe width | Shoe pads offered from about 356-457 mm (14-18 in). Narrower pads for Standard-gauge undercarriage, wider grouser pads for the LGP (low ground pressure) option. |
| Ground clearance | Not documented for a specific configuration in available literature -- verify against the OEM parts book for the exact serial range. |
Performance
| Transmission options | Two transmission types offered across the production run: a 5-speed selective spur-gear direct-drive unit (5 speeds forward and reverse), and a 3-speed planetary power-shift transmission built around Cat's torque-divider (a torque converter combined with a direct mechanical drive path). |
| Travel speed | Forward and reverse speeds are gear- and transmission-dependent and are not published in a single consolidated table for this model. Both direct-drive and power-shift ranges fall in the low single digits up to roughly 10 km/h (about 2-6 mph), typical for a dozer in this size class. Verify exact per-gear speeds against the power-train specification sheet for the specific serial range. |
| Drawbar pull | Rated drawbar pull (force) is not documented in available literature for this model -- verify with dealer or OEM literature for the specific serial range. |
| Ground pressure | Ground pressure figures are not documented in available literature for this model. Value depends on operating weight and the track shoe width fitted (Standard vs LGP) -- verify with dealer or OEM literature for the specific configuration. |
| Gradeability | Not documented in available literature for this model. |
| Hydraulic system (blade control) | Open-center hydraulic system, relief pressure about 8.6 MPa (1250 psi), pump flow about 76 L/min (20 gpm). Reported for a Special Application variant of the platform and representative of the family's blade-control circuit; confirm against the specific unit's parts book. |
Blades
| Blade types offered | Straight (S) dozer blade and angling (A) blade offered through the production run. A power-angle-tilt (6-way) blade option is documented in later production and aftermarket records. |
| Blade width | Straight blade commonly about 3.05 m (10 ft) wide. Narrower blades around 2.85 m (9.4 ft) are also reported for dirt-work configurations. Width varies by blade type and gauge fitted. |
| Blade capacity | Rated blade capacity (loose cubic yards/meters) is not documented in available literature for this model. Varies by blade type and width fitted -- verify with dealer or OEM literature. |
Service capacities summary
| Fuel tank | About 159 L (42 US gal) on the standard industrial/dozer tractor. A larger tank of about 248 L (65.5 US gal) is reported for the Special Application variant of the same platform. |
| Engine oil (crankcase) | About 18.9-20 L (20 qt). |
| Cooling system | About 30-32 L (32 qt). |
| Transmission oil | About 22.7 L (24 qt) in the direct-drive gear transmission; about 37.9 L (40 qt) in the power-shift transmission. |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
D4D fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | Varies by engine generation. Early D4D (D330/D330C 4-cyl engine, pre-82J-serial-break): approx. 22-23 L (5.8-6.1 US gal). Late D4D (3304 4-cyl engine, 82J-and-up): reported figures range roughly 12-17 L (12.7-18 qt) in dozer trim, though some 3304 application data runs up to about 31 L (8.3 US gal) for larger-sump variants. Confirm against the OMM for your serial prefix. | Cat Diesel Engine Oil (Cat DEO lineage). Original OMM-era spec called for single-grade SAE 30 across the normal ambient range, stepping down to SAE 10W or 10W-30 for cold-climate starts per Cat's viscosity-by-temperature chart. |
| Cooling system | Not documented for the D4D specifically. Comparable small Cat track-type tractors of this era with a 4-cylinder engine typically run in the 15-20 L (4-5 US gal) range. Verify with your dealer or the OMM for your serial prefix. | Cat ELC (Extended Life Coolant) or an equivalent low-silicate ethylene-glycol antifreeze/water mix per Cat's cooling system spec. Original-era spec called for a standard ethylene-glycol antifreeze plus a Cat corrosion/cavitation inhibitor additive, checked seasonally. |
| Fuel tank | approx. 159 L (42 US gal), per period D4D chassis reference data. Treat as approximate and confirm against the OMM for your serial prefix. | No. 2-D diesel fuel meeting Caterpillar's diesel fuel specification; No. 1-D diesel recommended for cold-climate operation. |
| Transmission + bevel gear/steering clutch compartment (Direct Drive configuration) | Combined approx. 22.7 L (6 US gal). Transmission and bevel-gear/steering-clutch sections share one splash-lubricated case, filled and checked via a single dipstick at the top of the compartment. | Cat TDTO (Transmission/Drive Train Oil), TO-4 spec, cross-referencing to TO-2 spec or Allison C-4 equivalents. Original OMM-era spec was single-grade SAE 30. |
| Main/master clutch compartment (Direct Drive, later-serial machines) | approx. 8 L (2-1/8 US gal), serviced separately from the transmission/bevel-gear case. | Same TDTO / TO-4 spec as the transmission; original spec was single-grade SAE 30. |
| Power Shift transmission (torque-converter-equipped D4D) | Not confirmed precisely for this configuration. Power-train refill capacity on Power-Shift-equipped D4D units (separate serial-prefix build, torque converter in place of the clutch/bevel-gear steering set) differs from the Direct Drive combined-case figure above and runs larger. Varies by serial prefix — verify with the OMM for your specific machine. | Same TDTO / TO-4 family oil used across the rest of the power train on this era of Cat dozer. |
| Final drives (each side) | Not consistently documented for the D4D specifically. Verify with the OMM for your serial prefix. | Same TDTO / TO-4 gear-oil family as the transmission and bevel-gear case. |
| Hydraulic system/tank (blade lift and angle circuit) | Not confirmed precisely for this system. Scheduled fluid change interval is roughly every 500-1,000 hours or annually. | Same TDTO / TO-4 family oil commonly shared across the D4D power train and hydraulic circuit on this era of machine. Keep fill equipment scrupulously clean — this circuit is sensitive to contamination. |
| Pivot shaft / equalizer bar | No separate oil-filled pivot-shaft compartment is documented for the D4D. On this size-class dozer, the equalizer-bar pivot is typically serviced through a grease fitting rather than an oil-filled case. | Cat Multipurpose Grease (NLGI 2, lithium-based EP) via grease fitting. |
| Grease (track, steering-clutch linkage, blade-lift points) | Not applicable — greased fittings, not a fluid-fill compartment. | Cat Multipurpose Grease (NLGI 2, lithium-based EP). High-wear track and linkage points greased daily (roughly every 10 operating hours) per era Cat practice; lighter-duty points at longer intervals per the lubrication chart. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar D4D maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
| Every 4,000 h |
|
| Every 8,000 h |
|
Servicing the D4D beyond the schedule
Predictive Maintenance & Fluid Analysis
Predictive service on a D4D means watching gauges and oil condition, not scan-tool codes; this machine predates electronics entirely. Pull the transmission oil screen after every drain and check for metal; on power-shift units it's the earliest warning of a clutch pack letting go. Watch the driveshaft between torque converter and transmission at full temperature: it should stop dead the instant a gear engages, any creep flags clutch wear early. Sample engine oil for bearing metal given the D330/3304's history of spun bearings.
Corrective & Common Repairs
D4D repairs cluster around a few recurring points. Steering that works cold but drags or won't turn after 20-30 minutes points to clutch discs slipping under heat, or a brake band soaked by a leaking steering-clutch seal; chase the seal before re-adjusting the band. Cracked cylinder heads and spun bearings recur, usually from overheating or low oil pressure; check the equalizer bar bolt bosses for cracking, a known weak spot. The DC generator and regulator fail often at the ground connection or worn brushes.
Overhaul & Rebuild Points
Overhaul planning centers on the D330/3304 block and the drivetrain it feeds. Cylinder head cracking and spun bearings are the recurring top-end failure, so a compression and oil-pressure check should precede any rebuild commitment. Steering clutch discs and brake bands wear together on direct-drive machines; power-shift torque converters and clutch packs wear together too, both showing up as hot-running slip. Undercarriage, pins, bushings, rollers, shoes, and the grease-tensioned track adjuster, is usually the largest rebuild item and is best budgeted as a set.
Seasonal & Environment Servicing
Cold starts rely on glow plugs alone, no ether, so hold the preheat switch 5-10 seconds warm, 30-60 seconds cold; a hard cold start is a glow-plug problem before it's an injection-pump problem. Hot, dusty duty cycles the radiator core and steering clutch harder; clean the core often and watch for clutch drag once at operating temperature. Machines stored outdoors need the track adjuster checked for tension loss and pivot points greased before layup, since a leaking adjuster is often the first thing to fail.
D4D common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 2P-7714 | Fuel Filter | Fuel system service | Check fitment → |
| 5S-9665 | Fuel Filter | Fuel system service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
D4D fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| Engine Oil Pressure gauge — low or zero reading | Oil pressure gauge needle drops toward zero or into the low range with the engine running. | Low engine oil level, worn oil pump, clogged suction screen or filter, worn main or rod bearings, or a faulty gauge or sending unit. | Stop the engine immediately. Check oil level and condition. Verify the gauge or sending unit before returning the machine to service. |
| Water Temperature gauge — needle in hot/red range | Coolant temperature gauge climbs into the hot zone during operation. | Low coolant level, plugged radiator core, slipping or broken fan belt, failed water pump, or on powershift-equipped units a failed transmission oil cooler feeding heat back into the coolant circuit. | Reduce load and idle down. Check coolant level and radiator core and fan belt once safe. On powershift units, inspect the transmission oil cooler and check for milky transmission fluid indicating cross-contamination. |
| Charging system / Ammeter — discharge reading or charge lamp on | Ammeter needle swings toward discharge, or the charging warning lamp stays lit with the engine running. | Loose or worn alternator/generator belt, corroded or loose battery cable connections, or a failed alternator/regulator. | Check belt tension and battery connections first. Test alternator output and regulator before condemning the battery. |
| Transmission/Torque Converter Oil Temperature gauge — high/red reading | On powershift-equipped D4D configurations, the transmission oil temperature gauge rises into the hot range, often alongside the coolant gauge since the two systems share an oil cooler. | Low transmission oil level, a plugged or failed transmission oil cooler, sustained high-load or stall operation, or internal torque converter wear. | Reduce load. Check transmission oil level and condition — milky fluid points to a cooler leak letting coolant mix in. Run a stall test to confirm gauge response and inspect the oil cooler. |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
D4D attachments & work tools
Blades
Factory blade lineup for the D4D covers a straight (S-type) push blade around 2.44 m (96 in) wide and a power-angling (A-type) blade around 3.09 m (121.6 in) wide with roughly 25 degrees of angle travel each side; both mount to the front C-frame as hydraulic-lift units. A true tall/curved U-blade or shorter S-U combination blade is not documented in factory literature for this class of dozer — those wider curved blades belong to larger Cat models. Variable Power Angle Tilt (VPAT) 6-way blading is a feature of the current-generation D4 reintroduced decades later and does not apply to this vintage D4D.
Rippers
The D4D sits at the small end of the ripper-equipped dozer range and is generally cataloged with a single-shank ripper as its practical factory-class option rather than a multi-shank unit. Multi-shank parallelogram rippers with their own hydraulic cylinder are also seen fitted to this dozer (shared fitment with the follow-on D4E), adding roughly 0.7-0.9 t of attachment weight depending on configuration — treat exact ripper weight as variable by shank count and vintage.
Winches
Rear-mounted cable winches for the D4D come from the same suppliers Caterpillar used across its small dozer line, chiefly Hyster and Allied Power. The winch most commonly paired with the D4D from the factory is rated for bare-drum line pull in roughly the 8.5-9 t (about 19,000-19,500 lb) range; a higher-capacity unit shared with the successor D4E, pulling closer to 11.7 t (about 25,800 lb) bare drum, is also commonly swapped onto D4D machines in the field since mounting patterns overlap. Winch fitment and pull rating varies by which-era winch is installed, so match by bolt pattern and drawbar casting rather than assuming one spec.
Drawbars/counterweights
A rear drawbar is standard fitment on the D4D for towing and also serves as the mounting/anchor point when a rear winch is fitted. No separate factory counterweight kit is documented for this model; the rear frame and drawbar casting provide the rear ballast needed for the blade sizes offered. Bare operating weight varies by configuration, roughly 8.2-8.8 t (about 18,000-19,445 lb) depending on blade and attachments equipped.
Cab/ROPS guarding
Factory configuration for the D4D era is an open operator station; a certified factory ROPS structure was not standard across this production run, though open sun/rain canopies were offered. For forestry or waste-handling use, aftermarket brush and debris screens are commonly retrofitted over the operator station and engine/radiator compartment to guard against branch and debris strikes, but this type of guarding is not a certified ROPS/FOPS structure on its own. Owners upgrading a D4D for forestry duty typically fit a certified ROPS retrofit kit as a separate item from any brush guarding.
Hydraulic arrangement (front/rear tools)
The D4D's hydraulic control valve is sized to the attachments fitted: a single valve section covers a blade-only machine, a second section is added when a ripper is fitted, and a third section covers a tilt cylinder when blade, ripper, and tilt are all present together. Pump output follows the same pattern — a lower-output pump (on the order of 17 gpm) suits blade-only/agricultural-style configurations, while a higher-output pump (on the order of 29 gpm) is fitted when ripper and tilt functions are both present. Front blade circuits (lift/angle) and the rear ripper circuit are separate valve sections off one pump rather than independent hydraulic systems.
All D4D assemblies by section
Every catalogued assembly group for the Caterpillar D4D. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Central Structure
5s6425 Balancer Group
| 5S***25 | Balancer Group; Balancer Group | 1 |
2p6201 Camshaft Group
| 2P***01 | Camshaft Group-Single; Single Camshaft Group | 1 |
5s6429 Connecting Rod And Piston Group
| 5S***29 | Connecting Rod And Piston; Connecting Rod And Piston Group | 1 |
6a6610 Cylinder Block Cover Group
| 6A***10 | Cover Group-Cylinder Block; Cylinder Block Cover Group | 1 |
Cylinder Block Cover (6a6610 N/S)
| 6A***10 | Cover Group-Cylinder Block; Cylinder Block Cover Group | 1 |
2p1686 Crankshaft Assembly--Field Installation
| 2P***86 | Crankshaft Assembly | 1 |
Crankshaft Bearing Replacement Groups
Crankshaft (2p6216 N/S)
| 2P***16 | Crankshaft Group | 1 |
6a6669 Cylinder Block Assembly
| 6A***69 | Cylinder Block As | 1 |
6a6609 Cylinder Block Cover Group
| 6A***09 | Cylinder Block Cover | 1 |
Cylinder Block Cover (6a6609 N/S)
| 6A***09 | Cylinder Block Cover | 1 |
6a3834 Cylinder Block Group
| 6A***34 | Cylinder Block Group; Cylinder Block Group | 1 |
4n4028 Connecting Rod And Piston Group
| 4N***28 | Piston & Rod Group; Connecting Rod And Piston Group | 1 |
9s8912 Connecting Rod And Piston Group
| 9S***12 | Piston & Rod Group; Connecting Rod And Piston Group | 1 |
2p6225 Crankshaft Seal Group
| 2P***25 | Seal Group-Crankshaft; Crankshaft Seal Group | 1 |
2p6223 Crankshaft Seal Group
| 2P***23 | Seal Group-Crankshaft; Crankshaft Seal Group | 1 |
Cooling System
2p6215 Engine Oil Cooler Group
| 2P***15 | Cooler Group-Engine Oil; Oil Cooler Group Engine | 1 |
2p6508 Transmission Oil Cooler Group
| 2P***08 | Cooler Group-Transmission Oil; Transmission Oil Cooler Group | 1 |
2p8167 Housing And Regulator Group
| 2P***67 | Housing & Regulator Group; Regulator And Housing Group | 1 |
2p8164 Housing And Regulator Group
| 2P***64 | Housing & Regulator Group; Regulator And Housing Group | 1 |
2p8169 Housing And Regulator Group
| 2P***69 | Housing & Regulator Group; Housing And Regulator Group | 1 |
2p8163 Housing And Regulator Group
| 2P***63 | Housing & Regulator Group; Housing And Regulator Group | 1 |
2p8165 Housing And Regulator Group
| 2P***65 | Housing & Regulator Group; Housing And Regulator Group | 1 |
3n3271 Housing And Regulator Group
| 3N***71 | Housing & Regulator Group; Housing And Regulator Group | 1 |
2p7740 Water Elbow Lines Group
| 2P***40 | Lines Group-Water; Water Lines Group--Elbow | 1 |
2p7741 Water Pipe Lines Group
| 2P***41 | Lines Group-Water; Water Lines Group-- Pipe | 1 |
2p6188 Water Lines
| 2P***88 | Lines Group-Water; Water Lines Group | 1 |
2p661 Water Pump
| 2P***61 | Pump Group-Water; Water Pump Group | 1 |
2p662 Water Pump
| 2P***62 | Pump Group-Water; Water Pump Group | 1 |
Engine Arrangement
5c785 Basic Engine Arrangement
| 2P***49 | Pipe Group-Exhaust; Exhaust Pipe Group | 0 |
| 2P***05 | Pulley Group; Pulley Group | 0 |
| 4N***79 | Exhaust Pipe Group | 0 |
5c790 Basic Engine Arrangement
| 2P***49 | Pipe Group-Exhaust; Exhaust Pipe Group | 0 |
| 2P***05 | Pulley Group; Pulley Group | 0 |
| 4N***79 | Exhaust Pipe Group | 1 |
Engine Arrangements
Front Structure
4n6508 Front Housing Cover Group
| 4N***08 | Cover Group-Front Housing; Front Housing Cover Group | 1 |
2p6529 Front Housing Cover Group
| 2P***29 | Cover Group-Front Housing; Front Housing Cover Group | 1 |
2p6528 Front Housing Cover Group
| 2P***28 | Cover Group-Front Housing; Front Housing Cover Group | 1 |
2p7831 Fan Drive Group
| 2P***31 | Drive Group-Fan; Fan Drive Group | 1 |
Fan Drive (4n8537 N/S)
| 4N***37 | Drive Group-Fan; Fan Drive Group | 1 |
Fan Drive (6a7389 N/S)
| 6A***89 | Fan Drive Group | 1 |
6a7389 Fan Drive Group
| 6A***89 | Fan Drive Group | 1 |
2p6498 Front Housing Fasteners Group
| 2P***98 | Fastener Group-Front Housing; Front Housing Fastener Group | 1 |
2p6498 Front Housing Fastener Group
| 2P***98 | Fastener Group-Front Housing; Front Housing Fastener Group | 1 |
2p6211 Front Gear Group--Timing
| 2P***11 | Front Gear Group; Front Gear Group-Timing | 1 |
2p6153 Front Housing Group
| 2P***53 | Front Housing; Front Housing Group | 1 |
2p9642 Front Timing Gear Group
| 2P***42 | Gear Group-Front Timing | 1 |
2p9642 Front Gear Group--Timing
| 2P***42 | Gear Group-Front Timing | 1 |
2p9641 Front Housing Group
| 2P***41 | Housing Group-Front; Front Housing Group | 1 |
2p8598 Crankshaft Hub Group
| 2P***98 | Hub Group-Crankshaft; Crankshaft Hub Group | 1 |
Pulley (2p8605 N/S)
| 2P***05 | Pulley Group; Pulley Group | 1 |
5c1987 Pulley Group
| 5C***87 | Pulley Group | 1 |
6a4274 Pulley Group
| 6A***74 | Pulley Group | 1 |
6a6620 Pulley Group
| 6A***20 | Pulley Group | 1 |
4n8281 Pulley Group--Type 1
| 4N***81 | Pulley Group; Pulley Group | 1 |
Pulley (6a5562 N/S)
| 6A***62 | Pulley Group | 1 |
6a6621 Pulley Group
| 6A***21 | Pulley Group | 1 |
4n8281 Pulley Group--Type 2
| 4N***81 | Pulley Group; Pulley Group | 1 |
Pulley (2p8610 N/S)
| 2P***10 | Pulley Group | 1 |
Pulley (4n3562 N/S)
| 4N***62 | Pulley Group-Crankshaft; Crankshaft Pulley Group | 1 |
2p7757 Support Group
| 2P***57 | Support Group | 1 |
5c2678 Support Group
| 5C***78 | Support Group | 1 |
2p7755 Support Group
| 2P***55 | Support Group-Engine | 1 |
2p7753 Support Group
| 2P***53 | Support Group-Engine; Front Engine Support Group | 1 |
4n5239 Support Group
| 4N***39 | Support Group-Engine; Engine Support Group | 1 |
2p6246 Trunnion Group
| 2P***46 | Trunnion Group-Engine | 1 |
Fuel System And Governor
9n867 Fuel Ratio Control Group
| 9N***67 | Control Group-Fuel Ratio | 1 |
6n2505 Torque Control Group
| 6N***05 | Control Group-Torque | 1 |
4n4510 Governor Cover Group
| 4N***10 | Cover Group-Governor; Governor Cover Group | 1 |
6n4413 Tachometer Drive Group
| 6N***13 | Drive Group-Tachometer; Tachometer Drive Group | 1 |
4n3303 Fuel Filter Group
| 4N***03 | Filter Group-Fuel; Fuel Filter Group | 1 |
2p975 Fuel Filter Group
| 2P***75 | Filter Group-Fuel; Fuel Filter Group | 1 |
Primary Fuel Filter (1p6835 N/S)
| 1P***35 | Filter Group-Primary Fuel; Primary Fuel Filter Group | 1 |
Fuel Filter (2p7714 N/S)
| 2P***14 | Fuel Filter | 1 |
5s9665 Fuel Filter Group
| 5S***65 | Fuel Filter | 1 |
6n5916 Fuel Filter Group
| 6N***16 | Fuel Filter Group | 1 |
Fuel Filter (5s9666 N/S)
| 5S***66 | Fuel Filter Group | 1 |
Fuel Injection Lines (2p7460 N/S)
| 2P***60 | Fuel Injection Lines | 1 |
Fuel Injection Lines (2p7461 N/S)
| 2P***61 | Fuel Injection Lines; Fuel Injection Lines Group | 1 |
4n3374 Fuel Injection Lines Group
| 4N***74 | Fuel Injection Lines Group | 1 |
6n728 Fuel Injection Lines Group
| 6N***28 | Fuel Injection Lines Group | 1 |
Fuel Injection Lines (6n727 N/S)
| 6N***27 | Fuel Injection Lines Group | 1 |
3n3387 Fuel Injection Pump Group
| 3N***87 | Fuel Injection Pump Group | 1 |
4n4882 Fuel Injection Lines Group--Part 2
| 4N***82 | Fuel Injection Valves And Lines Group | 1 |
4n4882 Fuel Injection Lines Group--Part 1 Of 2
| 4N***82 | Fuel Injection Valves And Lines Group | 1 |
4n4882 Fuel Injection Lines Group--Part 2 Of 2
| 4N***82 | Fuel Injection Valves And Lines Group | 1 |
5s2100 Fuel Priming Pump Group
| 5S***00 | Fuel Priming Pump | 1 |
Fuel Priming Pump (2p7716 N/S)
| 2P***16 | Fuel Priming Pump Group | 1 |
Fuel Priming Pump (7s1251 N/S)
| 7S***51 | Fuel Priming Pump Group | 1 |
Governor And Fuel Injection Pump (7s9334 N/S)
| 7S***34 | Fuel Pump Housing And Governor | 1 |
Governor And Fuel Injection Pump (8s727 N/S)
| 8S***27 | Fuel Pump Housing And Governor | 1 |
Governor And Fuel Injection Pump (8s720 N/S)
| 8S***20 | Fuel Pump Housing And Governor; Governor And Fuel Injection Pump | 1 |
Governor And Fuel Injection Pump (7s5859 N/S)
| 7S***59 | Fuel Pump Housing And Governor | 1 |
Governor And Fuel Injection Pump (8s728 N/S)
| 8S***28 | Fuel Pump Housing And Governor | 1 |
7s8831 Fuel Pump Housing Group
| 7S***31 | Fuel Pump Housing Group | 1 |
4n4900 Fuel Ratio Control Group
| 4N***00 | Fuel Ratio Control Group | 1 |
7s4430 Fuel Transfer Pump Group
| 7S***30 | Fuel Transfer Pump Group | 1 |
7s5445 Fuel Transfer Pump Group (7s5108 N/S)
| 7S***45 | Fuel Transfer Pump Group | 1 |
4n4873 Fuel Transfer Pump Group (7s5108 N/S)
| 4N***73 | Fuel Transfer Pump Group | 1 |
Glow Plug (5s8500 N/S)
| 5S***00 | Glow Plug Group; Glow Plug Group | 1 |
6n5356 Governor And Fuel Injection Pump Group--Part 3 Of 4
| 6N***56 | Gov & Fuel Inj Pump Group | 1 |
4n1834 Governor And Fuel Injection Pump Group--Part 3 Of 4
| 4N***34 | Gov & Fuel Inj Pump Group | 1 |
6n247 Governor And Fuel Injection Pump Group--Type 1
| 6N***47 | Gov & Fuel Inj Pump Group | 1 |
4n1834 Governor And Fuel Injection Pump Group--Part 1 Of 4
| 4N***34 | Gov & Fuel Inj Pump Group | 1 |
4n6115 Governor And Fuel Injection Pump Group
| 4N***15 | Gov & Fuel Inj Pump Group; Governor And Fuel Injection Pump Group | 1 |
6n5356 Governor And Fuel Injection Pump Group--Part 4 Of 4
| 6N***56 | Gov & Fuel Inj Pump Group | 1 |
6n284 Governor And Fuel Injection Pump Group--Replaced By 6n2476 Shown
| 6N***84 | Gov & Fuel Inj Pump Group | 1 |
6n5356 Governor And Fuel Injection Pump Group--Part 1 Of 4
| 6N***56 | Gov & Fuel Inj Pump Group | 1 |
4n1834 Governor And Fuel Injection Pump Group--Part 2 Of 4
| 4N***34 | Gov & Fuel Inj Pump Group | 1 |
4n6116 Governor And Fuel Injection Pump Group--Field Installation
| 1P***36 | Gasket; (Fuel Priming Pump)(Fuel Priming Pump) | 1 |
| 1P***53 | Stop Bar .250" (6.35 mm) Thick | 1 |
| 2H***34 | Seal Transfer Pump To Plate | 1 |
4n1834 Governor And Fuel Injection Pump Group--Part 4 Of 4
| 4N***34 | Gov & Fuel Inj Pump Group | 1 |
6n281 Governor And Fuel Injection Pump Group
| 6N***81 | Gov & Fuel Inj Pump Group; Governor And Fuel Injection Pump Group | 1 |
6n243 Governor And Fuel Injection Pump Group
| 6N***43 | Gov & Fuel Inj Pump Group | 1 |
6n279 Governor And Fuel Injection Pump Group
| 6N***79 | Gov & Fuel Inj Pump Group | 1 |
6n247 Governor And Fuel Injection Pump Group--Type 2
| 6N***47 | Gov & Fuel Inj Pump Group | 1 |
6n277 Governor And Fuel Injection Pump Group
| 6N***77 | Gov & Fuel Inj Pump Group; Governor And Fuel Injection Pump Group | 1 |
6n5356 Governor And Fuel Injection Pump Group--Part 2 Of 4
| 6N***56 | Gov & Fuel Inj Pump Group | 1 |
Governor And Fuel Injection Pump Group (6n249 N/S)
| 6N***49 | Governor And Fuel Injection Pump Group | 1 |
6n2477 Governor And Fuel Injection Pump Group
| 6N***77 | Governor And Fuel Injection Pump Group | 1 |
6n286 Governor And Fuel Injection Pump Group
| 6N***86 | Governor And Fuel Injection Pump Group | 1 |
6n244 Governor And Fuel Injection Pump Group--Type 2
| 6N***44 | Governor And Fuel Injection Pump Group | 1 |
6n283 Governor And Fuel Injection Pump Group
| 6N***83 | Governor And Fuel Injection Pump Group | 1 |
6n282 Governor And Fuel Injection Pump Group--Replaced By 6n2476 Shown
| 6N***82 | Governor And Fuel Injection Pump Group | 1 |
6n2476 Governor And Fuel Injection Pump Group--Replaced By 4n6116
| 1P***36 | Gasket; (Fuel Priming Pump)(Fuel Priming Pump) | 1 |
| 1P***53 | Stop Bar .250" (6.35 mm) Thick | 1 |
| 2H***34 | Seal Transfer Pump To Plate | 1 |
6n275 Governor And Fuel Injection Pump Group--Replaced By 6n2476 Listed
| 6N***75 | Governor And Fuel Injection Pump Group | 1 |
6n244 Governor And Fuel Injection Pump Group--Type 1
| 6N***44 | Governor And Fuel Injection Pump Group | 1 |
6n282 Governor And Fuel Injection Pump Group
| 6N***82 | Governor And Fuel Injection Pump Group | 1 |
6n274 Governor And Fuel Injection Pump Group--Replaced By 6n2476 Shown
| 6N***74 | Governor And Fuel Injection Pump Group | 1 |
7s9333 Governor Group--Part 2 Of 2--Type 3
| 7S***33 | Governor Group | 1 |
7s9332 Governor Group--Part 1 Of 2--Type 2
| 7S***32 | Governor Group | 1 |
7s9332 Governor Group--Part 2 Of 2--Type 1
| 7S***32 | Governor Group | 1 |
7s9333 Governor Group--Type 1
| 7S***33 | Governor Group | 1 |
7s9332 Governor Group--Part 2 Of 2--Type 2
| 7S***32 | Governor Group | 1 |
7s9333 Governor Group--Type 2
| 7S***33 | Governor Group | 1 |
7s9333 Governor Group--Part 1 Of 2--Type 3
| 7S***33 | Governor Group | 1 |
7s9332 Governor Group--Part 1 Of 2--Type 1
| 7S***32 | Governor Group | 1 |
Torque Control (8s5549 N/S)
| 8S***49 | Governor Torque Spring | 1 |
Torque Control (8s6099 N/S)
| 8S***99 | Governor Torque Spring | 1 |
Governor And Fuel Injection Pump (7s5858 N/S)
| 7S***58 | Injection Pump & Gov Group; Governor And Fuel Injection Pump Group | 1 |
9h2256 Fuel Priming Pump Assembly
| 9H***56 | Pump Assembly | 1 |
4n3287 Fuel Priming Pump Group
| 4N***87 | Pump Group-Fuel Priming; Pump Group-Fuel Priming | 1 |
Fuel Priming Pump (4n4314 N/S)
| 4N***14 | Pump Group-Fuel Priming; Fuel Priming Pump Group | 1 |
7s4429 Fuel Transfer Pump Group
| 7S***29 | Pump Group-Fuel Transfer; Fuel Transfer Pump Group | 1 |
4n4864 Fuel Transfer Pump Group--Type 1
| 4N***64 | Pump Group-Fuel Transfer | 1 |
4n4864 Fuel Transfer Pump Group--Type 2
| 4N***64 | Pump Group-Fuel Transfer | 1 |
Torque Control (9s3312 N/S)
| 9S***12 | Rack Stop Group | 1 |
Service Meter (9s7993 N/S)
| 9S***93 | Service Meter | 1 |
Service Meter (9s5141 N/S)
| 9S***41 | Service Meter | 1 |
Service Meter (9s8923 N/S)
| 9S***23 | Service Meter | 1 |
Service Meter Drive (2p6158 N/S)
| 2P***58 | Service Meter Drive | 1 |
Service Meter (2p6478 N/S)
| 2P***78 | Service Meter Group | 1 |
6n581 Torque Control Group
| 6N***81 | Torque Control Group | 1 |
Torque Control (6n509 N/S)
| 6N***09 | Torque Control Group | 1 |
Torque Control (9s3423 N/S)
| 9S***23 | Torque Spring Group | 1 |
Gasket Kits
Gasket Kits
| 5P***68 | Kit-Gasket; (Single Cylinder Liner)(Single Cylinder Liner) | 0 |
| 5P***71 | Water Pump- Serial No. 78p34523 To 78p40899 Inclusive | 0 |
| 5P***02 | 8n***60, 8n***61, 8n***15, 8n***16; 1w***78, 1w***79, 1w***86, 1w***87 | 0 |
Intake And Exhaust System
Accessory Drive (2p7712 N/S)
| 2P***12 | Accessory Drive | 1 |
Accessory Drive (2p7705 N/S)
| 2P***05 | Accessory Drive | 1 |
2p8711 Air Compressor Group
| 2P***11 | Air Compressor Group | 1 |
Air Compressor (2p7795 N/S)
| 2P***95 | Air Compressor Group; Air Compressor Group | 1 |
2p7794 Air Compressor Group
| 2P***94 | Air Compressor Group | 1 |
Air Compressor (2p8710 N/S)
| 2P***10 | Air Compressor Group; Air Compressor Group | 1 |
2p8709 Air Compressor Group
| 2P***09 | Air Compressor Group | 1 |
Air Compressor (2p8712 N/S)
| 2P***12 | Air Compressor Group; Air Compressor Group | 1 |
2p6837 Air Lines Group
| 2P***37 | Air Lines Group | 1 |
4n8279 Exhaust Pipe Group
| 4N***79 | Exhaust Pipe Group | 1 |
4n9585 Exhaust Manifold Fastener Group
| 4N***85 | Fastener Group-Exhaust Manifold; Exhaust Manifold Fastener Group | 1 |
4n9584 Exhaust Manifold Fastener Group
| 4N***84 | Fastener Group-Exhaust Manifold; Exhaust Manifold Fastener Group | 1 |
2p6533 Exhaust Manifold Fastener Group
| 2P***33 | Fastener Group-Exhaust Manifold; Exhaust Manifold Fastener Group | 1 |
Air Lines (6a7457 N/S)
| 6A***57 | Lines Group-Air; Air Lines Group | 1 |
Air Lines (2p6839 N/S)
| 2P***39 | Lines Group-Air; Air Lines Group | 1 |
2p6840 Air Lines Group
| 2P***40 | Lines Group-Air; Air Lines Group | 1 |
4n4794 Air Lines Group
| 4N***94 | Lines Group-Air; Air Lines Group | 1 |
6a7457 Air Lines Group
| 6A***57 | Lines Group-Air; Air Lines Group | 1 |
Air Lines (2p6843 N/S)
| 2P***43 | Lines Group-Air; Air Lines Group | 1 |
2p7796 Air Compressor Lines Group
| 2P***96 | Lines Group-Air Compressor; Air Compressor Lines Group | 1 |
4n3923 Turbocharger Oil Lines Group
| 4N***23 | Lines Group-Turbocharger Oil; Turbocharger Oil Lines Group | 1 |
4n3924 Turbocharger Oil Lines Group
| 4N***24 | Lines Group-Turbocharger Oil; Turbocharger Oil Lines Group | 1 |
Exhaust Manifold (2p6570 N/S)
| 2P***70 | Manifold Group-Exhaust; Exhaust Manifold Group | 1 |
Exhaust Manifold (2p6571 N/S)
| 2P***71 | Manifold Group-Exhaust; Exhaust Manifold Group | 1 |
2p7349 Exhaust Pipe Group
| 2P***49 | Pipe Group-Exhaust; Exhaust Pipe Group | 1 |
4n8737 Exhaust Pipe Group
| 4N***37 | Pipe Group-Exhaust; Exhaust Pipe Group | 1 |
3p138 Exhaust Pipe Group
| 3P***38 | Pipe Group-Exhaust; Exhaust Pipe Group | 1 |
1p34 Turbocharger Group (1p8533 N/S)
| 1P***34 | Turbocharger Group | 1 |
4n6857 Turbocharger Group
| 4N***57 | Turbocharger Group; Turbocharger Group | 1 |
1p9136 Turbocharger Group (1p9137 N/S)
| 1P***36 | Turbocharger Group | 1 |
4n6858 Turbocharger Group
| 4N***58 | Turbocharger Group | 1 |
4n6859 Turbocharger Group
| 4N***59 | Turbocharger Group | 1 |
4n6856 Turbocharger Group
| 4N***56 | Turbocharger Group; Turbocharger Group | 1 |
Turbocharger Oil Lines (2p7353 N/S)
| 2P***53 | Turbocharger Oil Lines Group | 1 |
Turbocharger Oil Lines (2p7430 N/S)
| 2P***30 | Turbocharger Oil Lines Group | 1 |
Lower Structure
2p6189 Oil Pan Fastener Group
| 2P***89 | Fastener Group-Oil Pan; Oil Pan Fastener Group | 1 |
2p6186 Oil Pan Fastener Group
| 2P***86 | Fastener Group-Oil Pan; Oil Pan Fastener Group | 1 |
2p6491 Oil Level Gauge Group
| 2P***91 | Gauge Group-Oil Level (Dipstick) | 1 |
2p990 Oil Level Gauge Group
| 2P***90 | Gauge Group-Oil Level (Dipstick) | 1 |
2p6494 Oil Level Gauge Group
| 2P***94 | Gauge Group-Oil Level (Dipstick); Oil Lever Gauge Group | 1 |
2p6175 Oil Pan Group
| 2P***75 | Pan Group-Oil; Pan Gp-Engine Oil | 1 |
Oil Pan (2p6155 N/S)
| 2P***55 | Pan Group-Oil; Oil Pan Group | 1 |
Lubrication System
Breather (1p4244 N/S)
| 1P***44 | Breather Group | 1 |
4n9821 Oil Filler Group
| 4N***21 | Filler Group-Oil; Oil Filler Group | 1 |
4n4817 Oil Filler Group
| 4N***17 | Filler Group-Oil; Oil Filler Group | 1 |
2p6855 Oil Filler Group
| 2P***55 | Filler Group-Oil | 1 |
2p6475 Oil Filter Group
| 2P***75 | Filter Group-Engine Oil; Oil Filter Group (10z1 ~ 10z7023) | 1 |
2p6525 Oil Filter Group
| 2P***25 | Filter Group-Oil | 1 |
Fumes Disposal (2p7446 N/S)
| 2P***46 | Fumes Disposal | 1 |
4n3325 Fumes Disposal Group
| 4N***25 | Fumes Disposal Group; Fumes Disposal Group | 1 |
2p7447 Fumes Disposal Group
| 2P***47 | Fumes Disposal Group | 1 |
3n3392 Fumes Disposal Group
| 3N***92 | Fumes Disposal Group; Fumes Disposal Group | 1 |
2p6512 Oil Lines Group
| 2P***12 | Lines Group-Engine Oil; Engine Oil Lines Group | 1 |
2p6513 Oil Lines Group
| 2P***13 | Lines Group-Engine Oil; Engine Oil Lines Group | 1 |
2p6857 Oil Filler Group
| 2P***57 | Oil Filler Group | 1 |
Oil Filler (2p6857 N/S)
| 2P***57 | Oil Filler Group | 1 |
2p1785 Oil Pump Group
| 2P***85 | Pump Group-Engine Oil | 1 |
2p1784 Oil Pump Group
| 2P***84 | Pump Group-Engine Oil; Engine Oil Pump Group | 1 |
Rear Structure
7s7753 Flywheel Group
| 7S***53 | Flywheel Group; Flywheel Group | 1 |
Flywheel (7s7878 N/S)
| 7S***78 | Flywheel Group; Flywheel Group | 1 |
Flywheel (7s7877 N/S)
| 7S***77 | Flywheel Group; Flywheel Group | 1 |
Flywheel (2p976 N/S)
| 2P***76 | Flywheel Group; Flywheel Group | 1 |
5c3176 Flywheel Housing Group
| 5C***76 | Flywheel Housing | 1 |
Flywheel Housing (5c3176 N/S)
| 5C***76 | Flywheel Housing | 1 |
5c3193 Flywheel Housing Group
| 5C***93 | Flywheel Housing Group | 1 |
2p6813 Flywheel Housing Group
| 2P***13 | Flywheel Housing Group | 1 |
Flywheel Housing (2p6166 N/S)
| 2P***66 | Housing Group-Flywheel; Flywheel Housing Group | 1 |
2p6166 Flywheel Housing Group
| 2P***66 | Housing Group-Flywheel; Flywheel Housing Group | 1 |
2p6119 Flywheel Housing Group
| 2P***19 | Housing Group-Flywheel; Flywheel Housing Group | 1 |
2p6119 Flywheel Housing Group--Type 1
| 2P***19 | Housing Group-Flywheel; Flywheel Housing Group | 1 |
2p6119 Flywheel Housing Group--Type 2
| 2P***19 | Housing Group-Flywheel; Flywheel Housing Group | 1 |
Upper Structure
Valve Mechanism Cover (2p6514 N/S)
| 2P***14 | Cover Group-Valve Mechanism; Valve Mechansim Cover Group | 1 |
4n7444 Cylinder Head Assembly
| 4N***44 | Cylinder Head Assembly | 1 |
2p6274 Cylinder Head Group
| 2P***74 | Cylinder Head Group; Cylinder Head Group | 1 |
2p6484 Cylinder Head Group
| 2P***84 | Cylinder Head Group; Cylinder Head Group | 1 |
Cylinder Head Fastener (2p6544 N/S)
| 2P***44 | Fastener Group-Cylinder Head; Cylinder Head Fastener Group | 1 |
1p3840 Lifting Eye Group
| 1P***40 | Lifting Group; Lifting Eye Group | 1 |
Valve Mechanism (2p6524 N/S)
| 2P***24 | Valve-Mechanism Group; Valve Mechanism Group | 1 |
D4D serial number reference
The PIN/serial tag sits on the upper rear face of the steering clutch case at the back of the tractor; if the tag has been knocked off, the number is often stamped directly into that housing. Fallback locations on some units include the left rear of the bevel gear case, the lower right rear of the firewall near the right steering brake pedal, or the frame rail beside the engine. The prefix is the leading letters-plus-digits code shown before the unit number (for example the 78A in 78A1273) and identifies the plant and production series; the digits that follow are the sequential unit count within that series, used to bracket parts and service manual coverage.
| Prefix | Identifies | Notes |
|---|---|---|
| 78A | US-built, 1st series, Direct Drive | Earliest D4D PIN series, built in the US. Direct-drive transmission with clutch-and-brake steering. D330/D330A 4-cylinder diesel, about 48 kW (65 hp) net. Production runs from the D4D's 1963 introduction into the mid-1960s. |
| 82J | US-built, 2nd series, Direct Drive | Follow-on US direct-drive series after 78A, with a revised final-drive design addressing early-series wear issues. Same D330-family engine lineage. |
| 83J | US-built, Power Shift | Power-shift transmission variant of the D4D, US production, forms its own parts/service manual break separate from the direct-drive 82J/84J series. Later units (mid-1970s) run wet steering clutches and brakes with an oil-cooled main clutch. |
| 84J | US-built, Direct Drive, special application | Direct-drive series that includes special-application tractors set up for disking and vineyard work. Early units carry the D330C engine at about 67 kW (90 hp); Caterpillar switched to the 3304 engine partway through the series. A factory-turbocharged special-application option later in the range raises output to about 80 kW (107 hp). |
| 85A | Australian-built, 1st series, Direct Drive | Australia-built counterpart to the US 78A series, same direct-drive configuration and D330-family engine. Roughly 1963-69 production window per surviving unit records. |
| 86A | French-built, 1st series, Direct Drive | France-built counterpart to the 78A/85A/91A group, same D330-family direct-drive configuration as the other 1st-series plants. |
| 88A | UK-built, 1st series, Direct Drive | UK-built counterpart to the 78A/85A/86A/91A group, mechanically the same 1st-series direct-drive design, differing mainly in electrical components. Owner reports describe more reliability issues on this plant's units than the US- or Japan-built equivalents. |
| 91A | Japan-built, 1st series, Direct Drive | Japan-built counterpart to the 78A/85A/86A/88A group, produced under the Caterpillar-Mitsubishi joint venture at the Sagami plant near Tokyo. Roughly 1966-69. |
| 66J | Japan-built series, Direct Drive | Japan-built D4D from the Caterpillar-Mitsubishi Sagami plant, late 1960s. Distinct parts/service-manual break from 91A; exact sequencing relative to 91A is not documented - confirm with dealer. |
| 22C | Power Shift, early series | Power-shift D4D parts manual break, factory-published mid-1967. Same power-shift line as the later 83J series. |
| 44H | Special application (confirm with dealer) | Distinct D4D special-application PIN break; one account ties a unit to 1971 French production. Note: a visible 44H tag on some machines may actually be the bulldozer blade's own serial rather than the tractor PIN - confirm with dealer before relying on this prefix alone for tractor identification. |
| 49J | D4D series (plant/configuration not documented - confirm with dealer) | A distinct D4D parts/service-manual serial break, grouped with the 82J/83J/65J/69K/74U series in factory service-manual scope. Plant, configuration, and year range are not documented for this prefix - confirm with dealer. |
| 59J | D4D series (plant/configuration not documented - confirm with dealer) | A distinct D4D parts/service-manual serial break, grouped with the 82J/83J/65J/69K/74U series in factory service-manual scope. Plant, configuration, and year range are not documented for this prefix - confirm with dealer. |
| 60J | D4D series (plant/configuration not documented - confirm with dealer) | A distinct D4D parts/service-manual serial break. One photographed unit is captioned as a 1975-built angle-blade dozer; treat the build year as unconfirmed - confirm with dealer. |
| 61J | D4D series (plant/configuration not documented - confirm with dealer) | A distinct D4D parts/service-manual serial break with its own parts-manual sub-breaks. Plant, configuration, and year range are not documented for this prefix - confirm with dealer. |
| 65J | Japan-built series, Direct Drive (confirm with dealer) | Reported as a Japan-built series from the Caterpillar-Mitsubishi joint venture, active roughly 1969-78; plant/year detail is not otherwise documented - confirm with dealer. |
| 69K | D4D series (plant/configuration not documented - confirm with dealer) | A distinct D4D parts/service-manual serial break, grouped with the 82J/83J/65J/74U series in factory service-manual scope. Plant, configuration, and year range are not documented for this prefix - confirm with dealer. |
| 74U | D4D series (plant/configuration not documented - confirm with dealer) | A distinct D4D parts/service-manual serial break, grouped with the 82J/83J/65J/69K series in factory service-manual scope. Plant, configuration, and year range are not documented for this prefix - confirm with dealer. |
| 7R | D4D series (plant/configuration not documented - confirm with dealer) | A distinct D4D parts/service-manual serial break in factory service-manual scope. Listings disagree on whether this is a French-built or a low-ground-pressure configuration; confirm plant and configuration with your dealer. |
| 97F | D4D series (plant/configuration not documented - confirm with dealer) | A distinct D4D parts/service-manual serial break in factory service-manual scope. Plant, configuration, and year range are not documented for this prefix - confirm with dealer. |
Frequently asked questions
What engine does the Caterpillar D4D use?
Early D4D production used the Cat D330 four-cylinder diesel rated around 65 hp (48 kW). A bore and displacement increase around 1972 raised output to roughly 74-75 hp (55-56 kW), and Caterpillar redesignated the same basic block the 3304 for the rest of the run. It is a mechanically governed, naturally aspirated engine with no electronics — check the serial prefix to know which version a given machine has.
What is the operating weight of a Caterpillar D4D?
It varies by configuration. A bare tractor with no blade runs about 5,900-6,900 kg (13,000-15,200 lb); a standard blade-equipped dozer runs about 8,200-9,400 kg (18,000-20,800 lb); heavier counterweighted agricultural or guarded builds reach roughly 10,900 kg (24,000 lb) without a blade. Confirm the exact figure for your serial range and equipment package rather than assuming a single number.
What replaced the Caterpillar D4D?
The Caterpillar D4E succeeded the D4D in the late 1970s, continuing the same D4-size crawler tractor class with updated engine and drivetrain hardware. The D4D itself had replaced Caterpillar's earlier D4-series crawler tractor.
What D4D owners discuss
What engine problems come up most with the Cat D4D, and does it use the D330 or the 3304?
The D4D left the factory with Cat's D330 direct drive diesel, a mechanically governed, naturally aspirated engine with no electronic controls. Partway through the model run Caterpillar redesignated this same basic block as the 3304, so you will see D4D nameplates paired with either D330 or 3304 tags depending on build date; treat them as the same engine family for service purposes, not two different motors. The recurring failure points owners and mechanics flag are cracked cylinder heads and spun main or rod bearings, usually tied to overheating or low oil pressure going unnoticed. A known structural weak spot is cracking around the equalizer bar bolt bosses on the underside of the block, worth a flashlight inspection on any used unit. Cold starting uses glow plugs only, no ether: hold the dash switch in the preheat position roughly 5 to 10 seconds on a warm engine and 30 to 60 seconds in cold weather before cranking, and treat a hard cold start as a glow plug problem before suspecting the injection pump. Because cracked heads and spun bearings mean a major teardown, have your dealer verify block and bearing condition with a compression and oil pressure check before you commit to a purchase or rebuild.
Why does D4D steering get worse as the machine warms up, and what is the fix?
This is one of the most repeated complaints in the field: steering works fine at startup, then after 20 to 30 minutes of work the machine barely turns or will not turn one way at all. That pattern points to steering clutch discs slipping under heat, usually from wear or from clutch oil that is contaminated or run low. Brake bands wear at the lining; if the adjustment bolt bottoms out with no travel left, the band is past service limit and needs relining or replacing, not just readjusting. A band that is oil soaked from a leaking steering clutch seal will keep slipping no matter how tight it is set, so chase the seal leak first. Pedal free play matters too: too little clearance drags the band and cooks it, too much lets the machine wander off line. Because a clutch or brake that fails hot is a steering control issue on a tracked machine, have your dealer verify steering clutch and brake band condition before the machine goes back to grade work.
D4D transmission: is it direct drive or power shift, and what goes wrong?
Caterpillar sold the D4D both ways: a direct drive version with a flywheel clutch, and a power shift version with a torque converter and hydraulic clutch packs. Owners generally say direct drive pulls implements better and runs cooler under sustained towing loads, while power shift suits dozer work since it changes direction without a clutch pedal. The classic power shift complaint is a gear that pulls fine cold but will not hold a load once the transmission reaches operating temperature, a sign of a clutch pack slipping from worn discs or dirty oil. The standard shop check is watching the driveshaft between converter and transmission at full temperature: it should stop dead the instant a gear engages, and any creep means that clutch is on its way out. Pulling the transmission oil screen after a drain is the first place mechanics look for early signs of a clutch letting go. Confirm which configuration a used machine has off the serial tag, since parts and expected behavior differ between the two.
What undercarriage wear patterns are typical, and why does track tension keep disappearing?
Track tension on the D4D is set through a grease hydraulic tensioner: pumping grease into the idler yoke extends it and takes up slack, and once set it should hold across normal operation. When owners report tension disappearing again and again, the cause usually traces back to a worn or leaking track adjuster yoke rather than the grease valve, especially on a machine where the adjuster is about the last tight component left in a tired undercarriage. Tension is normally checked with a straightedge across the top of the track; roughly 25 to 38 mm (1 to 1.5 in) of sag is the ballpark figure owners reference, though the exact spec varies by chain and roller wear stage, so confirm against the service manual for your machine. Watch for track shoes that foul the blade angle cylinders if oversized or mismatched shoes were fitted at some point, elongated pin and bushing holes, and rollers weeping lubricant. Undercarriage replacement is one of the largest line items on a machine this size, so weigh remaining wear life heavily before buying.
What hydraulic issues show up on the blade angle and tilt cylinders?
The most common hydraulic complaint is a blade that will not hold its angle or tilt setting and slowly drops or drifts on its own. Piston seal wear inside the cylinder is the first suspect; if the rod itself shows no external leak but the blade still creeps, the leak is internal past the piston. Cylinder rods should have a mirror finish, not a hazy or scored surface; a hazy rod points to seal and rod wear that will keep cutting new seals. Less common but documented is a piston that has separated from the rod internally after its retaining fastener backed out, which shows up as full loss of angle or tilt control with no visible leak anywhere. Chase leak down complaints control valve first, then cylinder seals, and check fluid condition and level before condemning a pump.
How does the D4D charging system behave, and what electrical faults are common?
The D4D left the factory with a DC generator and a separate voltage regulator, not an alternator, which trips up owners who try to diagnose it like a modern charging system. Since this machine predates any engine electronics, charging complaints are mechanical or wiring faults, not sensor or control module faults: a bad regulator ground, a poor connection at the regulator's sensing terminal, or worn generator brushes account for most of them. A bad regulator ground is worth checking first, because the regulator reads that connection as system voltage; if the ground is bad it reads no charge and keeps pushing current well past a safe level, which can boil or damage batteries. Because generator parts have gotten scarce, many owners convert to a one wire, negative ground alternator; on a healthy 24V system expect roughly 13V or more per battery bank with the engine running. Because overcharging can damage batteries and wiring or create a fire risk, have your dealer verify regulator function and charging output if you see boiling electrolyte, hot cables, or batteries that will not hold charge.
What should I check before buying a used D4D?
Start at the undercarriage: look at pins, bushings, rollers, and shoes for stretch and elongated holes, and confirm the track adjuster still has grease tensioning range left rather than being maxed out already. Pressure check the hydraulic system at the control valve to gauge pump and valve condition, and inspect cylinder rods for a mirror finish rather than scoring or haze. Work the steering clutch levers cold and again after 20 to 30 minutes of running to see if engagement gets soft or drags once hot, since a clutch that works cold but fails hot is one of the most common complaints on this machine. Check the final drive and rear end housings closely for cracking, particularly around mounting bosses if a winch is fitted or has been fitted in the past; this was a documented weak point on the D4D's direct predecessor and can still show up on early D4D production. Run the machine under real load, not just idle, and watch engine smoke color and power under load along with transmission behavior once everything is at full operating temperature. Because worn steering clutches, cracked final drive housings, and a slipping transmission are all safety and cost critical, have your dealer verify these systems with a proper inspection before you finalize a purchase.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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