Caterpillar D400D
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar D400D is a heavy-duty articulated dump truck designed for high-capacity earthmoving in rugged terrains. This machine features a 385 hp 3406 engine with an 891 cu in displacement. It offers a heaped capacity of 30.74 yd3 (23.5 m3) and a rated payload of approximately 79,986 lb (36,278 kg). The D400D series is characterized by its 34.85 ft (10.62 m) overall length and 10.83 ft (3.30 m) width, utilizing 29.5x25 radial tires for stability.
Across different production years, the D400D has maintained its core utility in quarrying and construction fleets. The machine remains a significant presence in the used equipment market due to the availability of the reliable 3406 engine series and standardized components. For operators managing older fleets, the D400D provides a balance of proven durability and accessible parts, making it a staple for secondary-market heavy haulage operations.
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 D400D specifications
Engine
| Engine Model | 3406 |
| Gross Power | 385 hp |
| Displacement | 891 cu in |
Weights
| Total Empty Weight | 61,789 lb |
| Total Loaded Weight | 141,774.9 lb |
| Rated Payload | 79,985.92 lb |
| Front Axle Weight (Empty) | 36,451.3 lb |
| Center Axle Weight (Empty) | 12,665.6 lb |
| Rear Axle Weight (Empty) | 12,665.6 lb |
Dimensions
| Overall Length | 34.85 ft in |
| Overall Width | 10.83 ft in |
| Overall Height | 11.68 ft in |
| Wheelbase | 19.85 ft in |
| Dump Height | 22.09 ft in |
| Heaped Capacity | 30.74 yd3 (23.5 m3) |
| Struck Capacity | 22.63 yd3 |
Performance
| Max Speed | 34.5 mph |
| Transmission Gears | 4 forward gears |
| Tire Size | 29.5x25 Radials |
Service capacities (summary)
| Fuel Capacity | 118.9 gal |
| Hydraulic Oil Specification | Cat HYDO Advanced Oils |
| Engine Oil Specification | Cat DEO, DEO-ULS |
| Transmission Fluid Specification | Cat TDTO |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
D400D fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | Not specified | CAT DEO or DEO-ULS; SAE 15W-40 or SAE 10W-30; for cold weather use SAE 0W-40 |
| Fuel tank | 450.1 liters (118.9 gal) | Not specified |
| Transmission/powertrain compartments | Not specified | CAT TDTO |
| Hydraulic system and tank | Not specified | Cat HYDO Advanced |
| Grease | Not specified | CAT Multipurpose Grease (low-load/low-speed); CAT Advanced 3Moly Grease (medium-load/medium-speed); CAT Ultra 5Moly Grease (high-load/high-speed) |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar D400D maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
Servicing the D400D beyond the schedule
Predictive Maintenance & Fluid Analysis
Utilize Cat S.O.S Services to monitor the 3406 engine oil and hydraulic systems. Analyze samples for wear metals like iron or copper, and check for contaminants such as silicon (dirt) or sodium (coolant). Monitoring hydraulic fluid particle counts and viscosity prevents catastrophic pump failure. Early detection of fuel dilution or water content in the fuel system allows for corrective action before engine damage occurs.
Corrective & Common Repairs
Frequent repair focus on the articulation joint, steering pins, and hydraulic hoses prone to abrasion. Monitor the 24V alternator and starter for electrical failures. If hydraulic performance drops, inspect the return filters and pump for cavitation damage caused by low fluid levels. Ensure all air conditioning compressor clutches are protected against voltage fluctuations to prevent component burnout during heavy duty cycles.
Overhaul & Rebuild Points
Major service milestones include transmission oil changes and comprehensive structural inspections of the chassis. Evaluate turbocharger integrity and ROPS bolt torque during PM3 intervals. When planning engine overhauls, focus on piston, ring, and bearing wear identified through oil analysis. For high-hour machines, a full hydraulic system flush and component evaluation is necessary to maintain rated payload efficiency.
Seasonal & Environment Servicing
In dusty or quarry environments, check air filter restriction daily and clean radiator fins frequently to prevent overheating. In extreme cold, utilize Cat Arctic Platinum Grease and appropriate cold-weather engine oils. For high-heat operations, shorten intervals for checking coolant SCA levels and hydraulic oil oxidation. Ensure all drains are cleared of debris to prevent moisture buildup in fuel and transmission systems.
D400D fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| 110-0 | Engine Coolant Temperature — Above Normal | Low coolant level or thermostat failure | Inspect cooling system and refill coolant |
| 110-3 | Engine Coolant Temp Sensor — Voltage High | Open circuit or sensor failure | Check wiring and replace sensor if faulty |
| 174-3 | Engine Fuel Temperature — Voltage Above Normal | Open circuit in sensor wiring | Inspect harness and replace sensor if necessary |
| 190-8 | Engine Speed — Abnormal Frequency | Speed sensor air gap, sensor failure, or tone ring damage | Check sensor gap and test speed sensor/tone ring |
| 41-3 | 8-Volt DC Supply — Voltage Above Normal | Short to power on 8V reference circuit | Inspect sensors sharing the 8V supply and isolate fault |
| 41-4 | 8-Volt DC Supply — Voltage Below Normal | Short to ground on 8V reference circuit | Disconnect sensors one at a time to locate short |
| 2458-2 | DPF #1 Differential Pressure — Erratic | Plugged pressure ports or failing sensor | Clean pressure ports and test sensor |
| E360 | Engine Coolant Temperature — High | Low coolant, failed thermostat, or water pump issue | Diagnose cooling system; do not operate until resolved |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
D400D attachments & work tools
Dump Body Attachments
Includes a 1/2 tailgate option for the truck body. This attachment is used to modify the discharge or containment characteristics of the dump box.
Mounting and Configuration
The machine utilizes a J Type mount for specific electrical components like the alternator. Standard tire configuration features 29.5x25 Radials or 29.5 R25 sizes.
Hydraulic and Fluid Systems
Systems require specialized fluids including Cat HYDO Advanced oils for hydraulic components. Engine lubrication requires Cat DEO or DEO-ULS diesel engine oil, while transmission systems utilize TDTO.
Operator Station Options
Aftermarket and replacement options include seats with 24V air suspension. These units are designed to retain the original OEM wire harness connector for compatibility.
All D400D assemblies by section
Every catalogued assembly group for the Caterpillar D400D. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Basic Engine
333-1672 Kit-Engine Parts
| 06***40 | Seal-O-Ring (Id=37.69mm) | 1 |
| 0T***00 | Plug (.5625" Diameter) | 1 |
| 10***47 | Cover-Flyweight | 1 |
321-1454 Kit-Hardware
| 00***01 | Ring-Retaining | 1 |
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 8 |
| 0T***65 | Bolt--3/8" X 3 1/2"--Use As Required; Bolt 5t***56 Plate To Cover Gp 4n***72 | 8 |
Engine Arrangement
333-1671 Conversion Ar-Engine
| 03***79 | Seal-O-Ring (Id=10.82mm) | 1 |
| 0R***39 | Pin-Piston | 1 |
| 0R***81 | Rod As-Connecting | 1 |
Fuel System
124-5658 Control Gp-Fuel Ratio
| 10***93 | Washer | 1 |
| 11***58 | Washer; (12.7x6.65x0.79-mm Thk) | 1 |
| 12***57 | Spring-Fuel Ratio Control | 1 |
9y-4913 Fastener Gp-Fuel Inj Pump -Governor
| 1B***16 | Bolt; (1/4-20x5-In) | 2 |
| 4F***57 | Screw,Cap,Hexagon H Shock Mount To Bracket | 2 |
| 5P***37 | Washer 5t***54 Plate To 7t***28 Cable As | 2 |
7c-4797 Governor Gp
| 03***16 | Bolt-Self Locking; (1/4unc X 3/4) | 3 |
| 0S***47 | Bolt; (1/4-20x0.75-In)(Drilled Head) | 2 |
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 1 |
111-9363 Pump Gp-Fuel Injection
| 0S***15 | Bolt 19 mm (.75 In.) Long Return Air Console To Enclosed Rops | 14 |
| 10***33 | Pump Group-Fuel Injection | 6 |
| 10***06 | Seal-O-Ring (10.52mm Id) | 1 |
108-6633 Pump Gp-Fuel Injection
| 10***02 | Bonnet-Valve | 1 |
| 10***04 | Plunger & Barrel As | 1 |
| 10***33 | Pump Group-Fuel Injection | 1 |
126-6710 Torque Control Gp
| 12***91 | Spring-Torque; (0.254-mm Thk) | 1 |
| 12***10 | Torque Control Group | 1 |
| 1P***52 | Insulator,Bushing Governor | 1 |
D400D serial number reference
The PIN plate is a durable metal identification plate usually riveted to the machine frame. To read the prefix, identify the first three alphanumeric characters of the serial number; these characters define the model generation and manufacturing factory.
| Prefix | Identifies | Notes |
|---|---|---|
| 8TF | D400D | Covers production from 1989 to 1996. Includes serial number range starting from 8TF1 and up. Verified by parts manual title and machine listings. |
Frequently asked questions
What engine is used in the Caterpillar D400D?
The D400D is powered by a Caterpillar 3406 engine with an 891 cu in displacement, producing 385 hp.
What is the total loaded operating weight?
The total loaded weight for the D400D is approximately 64,300 kg (141,774.9 lb).
What model replaced the D400D?
The provided documentation does not specify a direct successor model for the D400D.
What D400D owners discuss
What are the known engine performance and cooling issues for the Caterpillar D400D?
What should be inspected regarding the engine's electrical and sensor systems?
What are the common symptoms of fuel delivery problems in this series?
What exhaust smoke colors indicate specific mechanical failures?
What maintenance should be performed on the lubrication and cooling systems?
What should be checked when buying a used Caterpillar D400D?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
Need a specific D400D part?
Search live OEM part data, check fitment, and cross-reference alternatives with Heavy Parts AI.