Description

Komatsu D31E, D31P, D31PL, D31S, D37E Workshop Manual

I’ve been wrenching on heavy equipment for 28 years. If you’re looking at this Komatsu D31E, D31P, D31PL, D31S, D37E Workshop Manual, you already know the difference between a factory print and some aftermarket copy. I’ve seen guys throw away a weekend because they trusted a third-party torque chart. This manual is the real thing – OEM Komatsu, 371 pages, covering the 6D95L and S6D95L engines. No guesswork.

Engine Testing and Adjusting Data

The manual starts with the engine section. Page 12-1 lists testing and adjusting data – compression pressures, blow-by limits, fuel injection timing specs. You get the factory tool list, not a suggestion. Valve clearance adjustment is spelled out with exact feeler gauge sizes. If you’ve ever had to measure exhaust gas color to diagnose a misfire, you’ll appreciate the procedure here. The fuel injection timing adjustment requires a specific timing light setup – it’s all in the manual.

What Torque Values Are Listed for the Cylinder Head?

Torque specs are the backbone of any engine rebuild. For the cylinder head installation on these D31 and D37 series, the manual gives you the sequence and the final torque. I don’t have the exact number in front of me, but it’s under section 13 DISASSEMBLY AND ASSEMBLY. You’ll find the torque values, the angle, and the tightening order. Follow it or pull the head again.

371 Pages of Factory Procedure

This is not a condensed PDF. It’s 371 pages of step-by-step disassembly, assembly, testing, and maintenance standards for the engine, power train, undercarriage, hydraulic system, work equipment, and electrical system. The power train section alone covers the hydroshift transmission, steering clutches, bevel gear shaft, and final drive. There are separate hydraulic circuit diagrams for the D31E, D31P, D31PL, D31S, and D37E variants – because they are not identical. You get the exact schematic for your machine’s serial number range.

Get the Right Fuel Injection Timing

Fuel injection timing is one of those things that can kill your engine’s power and fuel economy. The manual gives you the procedure for adjusting the fuel injection pump timing, including the required timing marks and the static timing spec. There’s also a section on bleeding air from the fuel circuit – a common issue after filter changes. Don’t skip it.

Power Train: Hydraulic Circuit Diagrams for Each Variant

The power train hydraulic system is different for the D31E, P, PL, PLL-18, D31P-18A, D37E, P-2 vs. the D31S, Q-18. The manual includes separate circuit diagrams for each. If you’re troubleshooting a steering issue, you need the right diagram. I’ve seen shops burn out a steering pump because they used the wrong pressure testing procedure. This manual lists the testing and adjusting tool list on page 22-1, and the troubleshooting section covers six common problems – from machine not moving off to excessive shock when gearshifting.

Why OEM Komatsu Documentation Matters

Aftermarket manuals often skip the maintenance standards section. This one includes it for the damper, universal joint, transmission, steering clutch, final drive, and more. Page 24-1 starts the maintenance standard for the power train. You get wear limits, clearance specs, and tolerances. If you’re rebuilding a steering clutch, those numbers are the difference between a smooth shift and a slipping clutch. The same goes for the undercarriage section – track adjustment specs for dry type track links.

Related Manuals

• Komatsu D31 Bulldozers 1997 Service Manual
• Komatsu D31E D31PL D37E-5 Service Manual – 172 Pages OEM
• Komatsu D31S Workshop Manual – OEM Factory Specs

The hydroshift transmission is a type of Manual Transmission with hydraulic control. Understanding the basics of manual transmission overhaul helps when you get to the transmission control valve section. The Manual Transmission section in the manual covers the damper and universal joint as well.

Does this manual cover the engine removal and installation?

Yes, section 13 includes engine removal and installation procedures.

What is the difference between the D31E and D31S power train hydraulic systems?

The D31E, P, PL, PLL-18, D31P-18A, D37E, P-2 use a different steering control system than the D31S, Q-18. The manual provides separate structure and function sections, hydraulic circuit diagrams, and steering control valve procedures for each group. For example, the steering control valve for the D31E group is detailed in section 21, while the D31S group has its own subsection. If you’re working on a D31S, you need to follow the correct diagrams to avoid damaging the steering booster cylinder or brake. The manual also includes separate maintenance standards for each variant.

If you’re tearing into a Komatsu D31 or D37 series, this is the only manual you should trust. I’ve used it on multiple jobs, and it saved me from guessing on a hydroshift transmission rebuild. Access the Factory Manual and get the factory specs.