Komatsu DNH031_3K_D(S/N 45001-UP (D31P-20A))
Maintenance schedule, common problems & OEM parts breakdown
The Komatsu D31P-20A is a compact, mechanical crawler dozer in Komatsu's D31 class, built in the early-to-mid 1990s under the S/N 45001-up serial block. It runs the Komatsu 6D95L-1, a naturally aspirated diesel with mechanical jerk-pump fuel injection, driving a power-shift transmission through steering clutches and brakes rather than any electronic controls. Operating weight falls in roughly the 7.2 to 7.5 metric ton (15,850 to 16,500 lb) class, varying by blade and track configuration. The D31P-20A designation identifies the power-angle-tilt (PAT) blade version, sold alongside the straight-tilt D31P-20, wide-track D31PL-20 and D31PLL-20, and D31P-20T on the same serial block, with the D31P-18 as its direct predecessor.
Within the -20/-20A generation, Komatsu offered the same basic 6D95L-1 mechanical driveline across narrow-track, wide-track (LGP), straight-tilt, and power-angle-tilt blade configurations, letting buyers match undercarriage and blade type to the job without changing engine or drivetrain. This generation was Komatsu's last fully mechanical compact dozer platform before the D31PX-21 KOMSTAT II generation brought an electronically controlled transmission and a turbocharged engine, later followed by the D31PX-22. That mechanical simplicity (no ECM, no electronic fault codes, straightforward jerk-pump injection) is exactly why these machines still turn up in daily use decades later, and it keeps the used and parts market active: engine, undercarriage, and steering-clutch components are field-serviceable, and much of the driveline is shared across the D31E/P/PL/PLL-20 family even though blade linkage and attachment parts are configuration-specific.
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.
Komatsu DNH031_3K_D(S/N 45001-UP (D31P-20A)) specifications
Engine
| Engine model | Komatsu 6D95L-1, naturally aspirated diesel, mechanical (jerk-pump) fuel injection, no electronic engine controls. Engine and parts documentation for this serial range (S/N 45001-UP) tie this engine directly to the D31P-20A chassis book; other codes seen on some listings (S4D102E, 4D105) trace to different model suffixes or serial ranges and are not used here. |
| Gross power | Approx. 53 kW (71 hp) at 2,350 rpm |
| Displacement | Not documented for the 6D95L-1 on this exact serial range in available sources — verify with your dealer |
| Torque | Not documented for the 6D95L-1 on this exact serial range in available sources — verify with your dealer |
| Emissions certification | Pre-emissions mechanical diesel; no EPA/EU tier certification (1990s production era) |
Weights
| Operating weight | Reported range approx. 5,890-7,300 kg (12,985-16,094 lb) across sources; figures vary by blade configuration (this unit carries the Power Angle Tilt blade, which runs heavier than the straight-tilt D31P-20). Most consistent figure for this class is approx. 6,100-6,800 kg (13,450-15,000 lb) — verify against dealer plate/serial-specific data sheet |
Dimensions
| Overall length (with blade) | Approx. 3,940 mm (155.1 in) |
| Overall width (over blade) | Approx. 2,875 mm (113.2 in) |
| Overall height (to cab/canopy top) | Approx. 2,695-2,735 mm (106.1-107.7 in), varies by source |
| Width across tracks (track gauge + shoe) | Approx. 2,050-2,073 mm (80.7-81.6 in) |
| Track gauge (centerline) | Approx. 1,450-1,463 mm (57.1-57.6 in) on standard shoes; a wider gauge near 1,650 mm appears in one source, possibly a wide-track/LGP option, not confirmed for this exact serial range |
| Standard shoe width | 600 mm (23.6 in) |
| Length of track on ground | Approx. 2,185-2,195 mm (86.0-86.4 in) |
| Ground clearance | Not documented in available spec sheets for this serial range — verify with dealer |
Performance
| Travel speed, forward (max, 3-speed hydroshift) | Approx. 6.5-6.6 km/h (4.0-4.1 mph) |
| Travel speed, reverse (max, 3-speed hydroshift) | Approx. 7.2 km/h (4.5 mph) |
| Transmission | Hydroshift power-shift, 3 forward / 3 reverse gears |
| Ground pressure | Approx. 0.23-0.27 kg/cm2 (3.3-3.9 psi), varies by source/shoe width |
| Max drawbar pull | Approx. 87.9 kN (19,760 lb / 8,960 kgf) — single-source figure, not cross-confirmed |
| Gradeability | Not documented in available spec sheets for this serial range — verify with dealer |
Blades
| Blade type fitted (this configuration) | Power Angle Tilt (PAT) blade, per the parts-catalog designation for this S/N 45001-UP, D31P-20A configuration |
| Blade width | Approx. 2,875 mm (113.2 in) |
| Blade capacity | Approx. 1.3 m3 (1.70 yd3) — sourced from base D31P-20 spec data, not confirmed specific to the PAT blade fitted to this configuration; PAT blades can differ slightly in capacity from straight-tilt units |
| Max cutting depth | Approx. 320 mm (12.6 in) |
| Max blade lift height | Not documented in available spec sheets — verify with dealer |
Service capacities
| Fuel tank | 115 L (30.4 gal) |
| Cooling system | Approx. 22 L (5.8-5.9 gal) |
| Engine oil (with filter) | Approx. 14 L (3.7 gal) |
| Powertrain (transmission/torque converter) oil | Approx. 13.2 L (3.5 gal) |
| Final drive, each side | Approx. 9.8 L (2.6 gal) |
| Hydraulic (work equipment) pump flow | Approx. 90 L/min (24.0 gal/min) — this is pump flow rate, not tank capacity |
| Hydraulic tank capacity | Not documented in available spec sheets for this serial range — verify with dealer |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
DNH031_3K_D(S/N 45001-UP (D31P-20A)) fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase, with filter (6D95L-1 naturally aspirated diesel) | 14 L (3.7 US gal / 3.1 imp gal) | Diesel engine oil, API CD/CC service class. SAE 30 for ambient above 0°C (32°F); SAE 10W-30 for -15°C to 35°C; SAE 10W below -15°C (5°F). Komatsu genuine engine oil (EO-series) or equivalent. |
| Cooling system (radiator + block) | 22 L (5.8 US gal / 4.8 imp gal) | Clean water mixed with Komatsu genuine ethylene-glycol permanent-type antifreeze/coolant, ratio set for local minimum ambient temperature; add supplemental coolant additive per the periodic maintenance schedule. |
| Fuel tank | 115 L (30.4 US gal / 25.3 imp gal) | Diesel fuel, ASTM D975 No. 2-D for normal use; No. 1-D in cold climates. |
| Powershift transmission case | 13 L (3.4 US gal / 2.9 imp gal) | SAE 30 powertrain oil, API CD/CC (Komatsu TO-series or equivalent); switch to SAE 10W in cold-climate operation. |
| Bevel gear / steering clutch case | Reported between 20 L (5.3 US gal) and 47 L (12.4 US gal) depending on source — figures for this compartment vary by configuration/series; confirm the exact fill spec for this serial range with your dealer before servicing. | Same SAE 30 powertrain oil as the transmission (Komatsu TO-series or equivalent), API CD/CC; SAE 10W in cold climates. |
| Final drive case, each side | 9.5 L (2.5 US gal) with the 1450 mm standard-gauge undercarriage; 12 L (3.2 US gal) with the 1650 mm wide-gauge undercarriage — varies by track-gauge configuration | Same SAE 30 powertrain oil as the transmission and steering case (Komatsu TO-series or equivalent), API CD/CC; SAE 10W in cold climates. |
| Hydraulic system / tank (blade lift, angle, tilt circuit) | Not documented as a standalone reservoir figure in available sources for this serial range. On this generation the blade hydraulic circuit commonly draws from the shared powertrain oil supply rather than a separate hydraulic tank; verify with your dealer. | Same powertrain oil as transmission/final drive (SAE 30, Komatsu TO-series or equivalent), API CD/CC. |
| Pivot shaft | Not listed as a distinct lubrication point in available sources for this model. | Not documented for this serial range; if equipped, service per the equalizer-bar/track-frame grease schedule. |
| Grease (chassis points: track idler, equalizer bar center pin, blade linkage, etc.) | Apply at each fitting until fresh grease purges — no reservoir capacity applies. | Komatsu genuine multipurpose grease, NLGI No. 2 for normal temperatures; NLGI No. 0 or No. 1 for sub-freezing climates. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Komatsu DNH031_3K_D(S/N 45001-UP (D31P-20A)) 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 |
|
Servicing the DNH031_3K_D(S/N 45001-UP (D31P-20A)) beyond the schedule
Predictive Maintenance & Fluid Analysis
This machine carries no ECM, so oil and coolant sampling are the only real predictive tools on the 6D95L-1 engine. Pull engine oil samples near every 250-hour change to track wear metals from the mechanical injection pump and cylinder liners before they show up as smoke or low compression. Sample power-shift transmission oil at 500-hour intervals to catch clutch-plate wear early. Watch coolant for additive depletion and check the fuel water separator often; jerk-pump injection is unforgiving of contaminated fuel.
Corrective & Common Repairs
Most repair calls on this dozer trace to the mechanical fuel system or the steering clutch and brake linkage. Hard starting or power loss usually means a worn injection pump plunger, a clogged dry-type air cleaner, or air in the fuel lines after a filter change. Steering clutch and brake pedals that creep out of adjustment point to worn linkage or disc wear, not an electronic fault. On the PAT blade, check the angle and tilt cylinders for rod seal leaks before assuming a pump problem.
Overhaul & Rebuild Points
Undercarriage wear drives most overhaul decisions on this compact dozer. Inspect track link and bushing wear and sprocket tooth profile well before pins and bushings turn; the small frame concentrates ground pressure on fewer rollers than larger Komatsu dozers. When steering clutches and brakes reach the end of adjustment, plan a full pack rebuild rather than repeated relining. On the 6D95L-1, budget for liner, piston, and valve-train work once compression drops and oil consumption climbs, since this naturally aspirated engine has no turbo to mask top-end wear.
Seasonal & Environment Servicing
Cold starts are harder on this naturally aspirated mechanical engine than on later turbocharged D31 generations, so check glow plug or intake heater function and use a winter-grade fuel blend to avoid gelling in the jerk-pump lines below freezing. In hot, dusty sites, shorten the dry-type air cleaner service interval and check the dust indicator daily rather than by the hour meter. Wet or coastal environments call for more frequent steering clutch linkage and track adjuster greasing to keep moisture and grit from accelerating wear.
DNH031_3K_D(S/N 45001-UP (D31P-20A)) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 113-60-43321 | Cartridge,Hydraulic Oil Filter (D31s) | Hydraulic service | Check fitment → |
| 07002-03334 | O-Ring, At Transmission Filter | Scheduled service item | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
DNH031_3K_D(S/N 45001-UP (D31P-20A)) fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| Engine oil pressure lamp (red, oil-can symbol) | Engine lube oil pressure below safe minimum | Low oil level, worn oil pump, clogged filter, or failed pressure switch/sender | Stop engine immediately, check oil level and filter condition before restart |
| Charge lamp (red, battery symbol) | Alternator not charging the battery circuit | Broken/slipping fan belt, failed alternator, or wiring fault | Check belt tension and alternator wiring; replace alternator if belt is intact |
| Coolant temperature gauge in red zone / overheat lamp | Engine coolant temperature above normal operating range | Low coolant, clogged radiator fins, failed thermostat, or slipping fan belt | Idle down, let engine cool, check coolant level and radiator for debris before continuing work |
| Air cleaner (dust indicator) clog signal | Air filter restriction has reached the service limit | Dust-clogged element from dry/dusty jobsite conditions | Service or replace the air cleaner element, reset the dust indicator |
| Fuel level low warning (gauge needle in red) | Fuel tank near empty | Normal consumption, not a fault | Refuel; bleed the mechanical injection fuel system if the tank was run fully dry |
| Preheat (glow) indicator lamp | Intake air preheating device is active for cold start | Normal cold-start function | Wait for lamp to go out before cranking; if it never illuminates, check the preheat circuit fuse/relay |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
DNH031_3K_D(S/N 45001-UP (D31P-20A)) attachments & work tools
Blades
This D31P-20A (S/N 45001-up) is the power-angle-tilt (PAT) blade version of the D31 small-class dozer, per the parts-catalog designation tied to this exact serial book — distinct from the straight-tilt D31P-20 sharing the same serial range. Blade width runs close to the machine's over-blade width, in the 2,800-2,900 mm (110-114 in) class; exact height and capacity figures specific to the PAT blade are not separately published, so treat capacity as a class-typical low-1 m3 range rather than a confirmed A-suffix number. Full VPAT (variable-pitch angle-tilt) is a feature reserved for larger Komatsu dozer classes (D65 and up) and is not a documented option on this D31-class machine.
Rippers
Rear ripper attachments for this D31 class are multi-shank, parallelogram-style units (commonly 2-3 shank pockets) actuated by a pair of hydraulic cylinders rather than a single-shank giant ripper, which is reserved for larger dozer classes. Exact shipping weight for the ripper attachment is not documented in available sources; expect a modest add-on weight consistent with a sub-8-tonne machine class - verify with dealer parts data for an exact figure.
Winches
Pre-2000s small Komatsu dozers in this D31/D37/D39 family were commonly fitted with a PTO-driven cable winch rather than a hydraulic winch; aftermarket sources tie a roughly 13-14 tonne (about 30,000 lb) class winch (of the type built for the D31/D37/D39 dozer family) to this chassis. A hydraulic winch option exists on later/related Komatsu small-dozer generations, but is not confirmed as a factory option specifically for this earlier D31P-20A mechanical-engine build - verify PTO provision with the shop manual for this serial range.
Drawbars/counterweights
A rear drawbar/pintle-type towing hitch is standard equipment on this class of dozer for towing or winch-line routing duties. Specific counterweight kits (used when running a rear ripper or winch instead of a rear blade/tool) are typical across this dozer size class, but no model-specific weight or part detail is documented for the D31P-20A configuration in available sources - confirm with dealer.
Cab/ROPS guarding
The factory service literature for this range explicitly covers both a ROPS-canopy version and an enclosed-cab version of this machine, so both guarding baselines exist for this serial range. Forestry/waste-handling guarding on this class of small dozer typically adds wire-mesh or polycarbonate window guards and a rear screen/sweep over the ROPS or cab glass; these are aftermarket/dealer-fit protective packages rather than a documented Komatsu factory forestry option for this specific A-suffix model - verify availability with your dealer.
Hydraulic arrangement
Front blade lift/tilt (and angle, if the PAT blade is fitted) runs off the machine's main hydraulic pump through dedicated double-acting circuits routed to the front of the tractor. A rear-mounted multi-shank ripper needs its own lift/tilt double-acting circuit plumbed to the back of the machine, separate from the blade circuit. A PTO-driven winch, where fitted, is mechanically clutched off the transmission rather than hydraulically powered, so it does not compete with the blade/ripper hydraulic circuits for pump capacity.
All DNH031_3K_D(S/N 45001-UP (D31P-20A)) assemblies by section
Every catalogued assembly group for the Komatsu DNH031_3K_D(S/N 45001-UP (D31P-20A)). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Guard
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Guard : Rear Cover And Hydraulic Tank (For 3-Point Hitch And P.T.O.) (Noise Suppression For Ec)(#45001-46504)
| 01***25 | Bolt,Without Revolution Sensor | 3 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 20 |
| 01***40 | Bolt,R.H. Outside And L.H. Inside, Bolt | 4 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Guard : Rear Cover And Hydraulic Tank (For 3-Point Hitch And P.T.O.) (Regulation Of Eu Dynamic Noise)(#46505-)
| 01***16 | Bolt (With Air Heater & Conditioner) | 2 |
| 01***25 | Bolt,Without Revolution Sensor | 3 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 20 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Guard : Rear Cover And Hydraulic Tank (For 3-Point Hitch) (For 2-Pillar Type Canopy)
| 01***25 | Bolt,Without Revolution Sensor | 3 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 20 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 2 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Guard : Rear Cover And Hydraulic Tank (For 3-Point Hitch) (For 4-Pillar Type Canopy)
| 01***25 | Bolt,Without Revolution Sensor | 3 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 20 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 2 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Guard : Rear Cover And Hydraulic Tank (With Rops Cab) (For 3-Point Hitch And P.T.O)
| 01***25 | Bolt,Without Revolution Sensor | 3 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 20 |
| 01***40 | Bolt,R.H. Outside And L.H. Inside, Bolt | 4 |
Hydraulic System
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Hydraulic System : Hydraulic Piping (3-Point Hitch Cylinder Line) (Chassis Side)
| 01***20 | Bolt, Wiring Harness Mounting Bracket | 3 |
| 01***09 | Nut,(With Body Positioner) | 4 |
| 01***25 | Washer,Spring?For Additional Rear Lam | 1 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Hydraulic System : Hydraulic Piping (Tank To Pump To Valve) (For 3-Point Hitch)(#45001-47616)
| 01***40 | Bolt,(With Air Conditioner) | 4 |
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 1 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 4 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Hydraulic System : Hydraulic Tank And Filter (For 3-Point Hitch) (Except Japan)
| 01***35 | Bolt,(For Quick Shift) (Mitsubishi) | 5 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 6 |
| 01***16 | Bolt - Starting Motor Ground Cable | 2 |
Operator'S Compartment And Control System
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Operator'S Compartment And Control System : Work Equipment Control Lever (1/2) (For 3-Point Hitch)
| 01***16 | Bolt - Seat And Tether Belt Mounting | 4 |
| 01***25 | Bolt,(Rear Attachment Less) | 1 |
| 01***30 | Bolt - M8 X 30lg | 3 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Operator'S Compartment And Control System : Work Equipment Control Lever (2/2) (For 3-Point Hitch)
| 01***25 | Bolt,(Rear Attachment Less) | 6 |
| 01***05 | Nut,L.H. (For Trimming Dozer) | 1 |
| 01***06 | Nut,(With Back-Up Alarm) (Op), Nut; Was 01580-10806 | 1 |
Service Kit And Component Parts
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Service Kit And Component Parts : 3-Point Hitch Cylinder
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 1 |
| 01***26 | Nut,Nylon | 1 |
| 01***09 | Nut,(With Body Positioner) | 2 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Service Kit And Component Parts : Control Valve (3-Spool) (1/3)(#47617-)
| 01***25 | Bolt, Seal Cover Mounting | 4 |
| 01***12 | Bolt | 4 |
| 01***30 | Bolt | 2 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Service Kit And Component Parts : Control Valve (3-Spool) (2/3)(#47617-)
| 01***12 | Bolt | 2 |
| 01***30 | Screw | 2 |
| 07***34 | O-Ring,(For Without Brake Assistor) | 4 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Service Kit And Component Parts : Control Valve (3-Spool) (3/3)(#47617-)
| 07***34 | O-Ring, O-Ring, Oil Level And Fill Plug | 2 |
| 07***34 | O-Ring, At Transmission Filter | 1 |
| 70***61 | O-Ring,(Pc100ss) | 1 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Service Kit And Component Parts : Control Valve (4-Spool) (1/3) (For 3-Point Hitch)(#45001-47616)
| 01***20 | Bolt (Itl) | 4 |
| 01***25 | Bolt, Seal Cover Mounting | 4 |
| 01***30 | Bolt (Itl) | 2 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Service Kit And Component Parts : Control Valve (4-Spool) (1/3) (For 3-Point Hitch)(#47617-)
| 01***12 | Bolt | 4 |
| 01***25 | Screw | 4 |
| 01***30 | Bolt | 2 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Service Kit And Component Parts : Control Valve (4-Spool) (2/3) (For 3-Point Hitch)(#45001-47616)
| 01***20 | Bolt (Itl) | 2 |
| 01***30 | Bolt | 6 |
| 07***30 | Ring, Seal - Between Sections | 2 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Service Kit And Component Parts : Control Valve (4-Spool) (2/3) (For 3-Point Hitch)(#47617-)
| 01***12 | Bolt | 2 |
| 01***30 | Screw | 6 |
| 07***38 | O-Ring, (Without Emergency Steering) | 2 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Service Kit And Component Parts : Control Valve (4-Spool) (3/3) (For 3-Point Hitch)(#45001-47616)
| 07***34 | O-Ring, O-Ring, Oil Level And Fill Plug | 3 |
| 07***34 | O-Ring, At Transmission Filter | 1 |
| 07***34 | O-Ring,(F2310-59a0 -4 ) | 1 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Service Kit And Component Parts : Control Valve (4-Spool) (3/3) (For 3-Point Hitch)(#47617-)
| 07***34 | O-Ring, O-Ring, Oil Level And Fill Plug | 2 |
| 07***34 | O-Ring, At Transmission Filter | 1 |
| 07***34 | O-Ring,(F2310-59a0 -4 ) | 1 |
Work Equipment
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Work Equipment : 3-Point Hitch (1/2)
| 01***20 | Bolt,(For Quick Shift) (Mitsubishi) | 6 |
| 01***50 | Bolt,(For Tree Pusher) | 10 |
| 01***80 | Bolt,(For 100kg) | 6 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Work Equipment : 3-Point Hitch (2/2)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 6 |
| 01***38 | Nut | 2 |
| 01***30 | Washer, Spring (Supplied W/Spider Assembly), Washer-Spring | 6 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Work Equipment : Drawbar (For 3-Point Hitch)
| 01***55 | Bolt,(With Hook) | 4 |
| 01***12 | Washer,(With Body Positioner) | 1 |
| 01***60 | Flat Washer - M20 (Hardened) | 4 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Work Equipment : Hydraulic Piping (Valve To Cylinder) (For 3-Point Hitch)
| 01***20 | Bolt,(With Auto Emergency Steering) | 2 |
| 01***25 | Washer,Spring?For Additional Rear Lam | 2 |
| 01***23 | Washer, Wiring Harness Mounting Bracket | 2 |
Komatsu : Dnh031_3k_d(S/N 45001-Up (D31p-20a)) : Work Equipment : Swing Drawber (For 3-Point Hitch)
| 01***55 | Bolt,(With Hook) | 10 |
| 01***80 | Bolt,(For 100kg) | 4 |
| 01***60 | Flat Washer - M20 (Hardened) | 14 |
DNH031_3K_D(S/N 45001-UP (D31P-20A)) serial number reference
On this generation of D31 dozer the serial/PIN plate sits low in the operator's station, near the floor under the seat by the steering and drive control handle area, not on a frame rail like later PIN-era Komatsu machines. The plate (or a stamped pad if the plate is missing) shows the full model code and a plain numeric serial number, no 3-character alpha prefix. For this book that number reads 45001 or higher. Read the number as-is against the 45001-UP break to confirm it falls in this D31P-20A range and not the sibling D31P-20 straight-tilt or D31E-20 books, which use overlapping or separate serial starts.
| Prefix | Identifies | Notes |
|---|---|---|
| 45001-UP | D31P-20A Power Angle Tilt dozer, base range | Book break opening the D31P-20A (Power Angle Tilt Dozer) parts manual set for S/N 45001 and up. A separate straight-tilt D31P-20 (non-A) book also opens at S/N 45001-UP; it is a distinct book/configuration, not the same as this D31P-20A range. Serials on this vintage machine are plain numeric with no alpha PIN prefix to decode. |
| 6D95L-1 | Factory engine, D31P-20A 45001-UP | Naturally aspirated 6-cylinder diesel, mechanical injection, no ECM. Parts documentation pairs this engine family (AC-E/AC-P variants, engine S/N 96999-up) directly with the D31P-20A 45001-UP chassis book. This is the engine for this serial range. |
Frequently asked questions
What engine powers the Komatsu D31P-20A (S/N 45001-up)?
It uses the Komatsu 6D95L-1, a naturally aspirated diesel with mechanical jerk-pump fuel injection and no electronic engine controls or fault codes.
What is the operating weight of the D31P-20A?
Factory-era literature for this configuration puts it at roughly 5,890-7,300 kg (12,985-16,094 lb) depending on source, most commonly cited around 6,100-6,800 kg (13,450-15,000 lb). Confirm against your machine's nameplate or dealer for a precise number.
What replaced the Komatsu D31P-20A?
Komatsu replaced it with the D31PX-21 (KOMSTAT II generation), which added an electronically controlled power-shift transmission and a turbocharged engine. That line was later succeeded by the D31PX-22.
What DNH031_3K_D(S/N 45001-UP (D31P-20A)) owners discuss
What engine does the D31P-20A (S/N 45001-up) actually run, and are there known quirks?
Is the steering clutch/turning behavior on these dozers something to worry about?
Do owners report transmission or final drive oil issues?
What undercarriage wear pattern should I expect on a D31-class dozer like this?
Are there known electrical or charging system complaints?
Any hydraulic system complaints specific to blade/lift function?
What should I inspect before buying a used D31P-20A in this serial range?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
Need a specific DNH031_3K_D(S/N 45001-UP (D31P-20A)) part?
Search live OEM part data, check fitment, and cross-reference alternatives with Heavy Parts AI.