Description

Komatsu D155A-2 2002 Service Manual

I’ve seen too many guys slap a dozer back together with a generic manual or worse, no manual at all. Then they wonder why the transmission slips or the torque converter runs hot. This Komatsu D155A-2 2002 Service Manual is what you should have on the bench if you’re doing anything beyond an oil change. 462 pages of factory-issued procedures, not some photocopied aftermarket mess. You get the actual specs Komatsu used when this machine left the Osaka plant.

Engine Testing: Standard Value Tables and Adjustments

The Testing and Adjusting section (starting around page 20-1) is where you’ll spend most of your time if you’re chasing performance or diagnosing a miss. It lays out standard value tables for engine functions: intake manifold pressure (boost), exhaust temperature, blowby pressure, and compression pressure. Valve clearance adjustments are right there too – hot or cold, intake and exhaust. Fuel injection timing inspection and adjustment procedures are included. Don’t trust a chart you found online; use the factory values from this 2002 Service Manual.

Transmission and Torque Converter Specs

You cannot rebuild a D155A-2 power train without knowing the torque converter stalling revolution rate and the transmission control pressures. This manual covers the entire power train system: torque converter, transmission control valve, lubrication relief valve, and the steering main relief valve. It gives you the oil pressure test points and the adjustment strokes for linkages. If you’ve ever had a machine that won’t shift or lurches on engagement, the troubleshooting section (H-mode) walks you through the hydraulic and mechanical checks step by step.

Valve Clearance and Fuel Injection Timing

Every engine needs its valves set right and its injection timing spot-on. The manual includes specific procedures for measuring and adjusting valve clearance – no rounding, no guessing. Fuel injection timing inspection uses a timing light and the marks on the flywheel. Compression pressure measurement tells you if the rings or valves are shot before you tear it down. These aren’t generic steps; they’re the ones Komatsu engineers wrote for the SA6D140-2 engine in the D155A-2.

Troubleshooting Flow Diagrams – Find the Fault Fast

When the machine won’t start, the headlamps don’t work, or the pin puller cylinder acts up, you don’t have time to reinvent the wheel. This manual has dedicated flow diagrams for electric equipment (E-mode) and hydraulic/mechanical systems (H-mode). Each fault code like E-1 (engine does not rotate) gives you a decision tree: check connectors, measure voltage, follow the path. The connector pin number tables and actual electric wiring diagrams are in the Structure and Function section. For a basic refresher on how a Manual Transmission operates, you can reference the Manual Transmission article on Wikipedia – but for this specific machine, the manual’s power train hydraulic circuit diagram is your real guide.

Why OEM Documentation Beats Aftermarket Reprints

I’ve had to fix too many machines where a previous mechanic used aftermarket specs and torqued something to the wrong value. Aftermarket manuals often skip details or use generic drawings. This 2002 Service Manual is an original Komatsu publication – it has the part numbers, the bolt grades, and the exact torque sequence for the cylinder head and transmission. The Table of Fuel, Coolant and Lubricants on page 01 tells you exactly what fluids to use. No guesswork. For a general explanation of how a Manual Transmission works, the Manual Transmission entry on Wikipedia can help, but the specific valve body and clutch pack specs are only in this OEM manual.

Related Manuals

• Komatsu D155A-2 2002 Workshop Manual – OEM Factory Repair
• Demag Komatsu H 285 S Service Manual – 544 Pages of Factory Specs
• Komatsu WA430-6 Service Manual – 306-Page OEM Shop Manual

FAQ

Does the manual cover the fuel system?

Yes. Page 01 includes the table of fuel, coolant, and lubricants.

What torque values are listed for the cylinder head?

The manual provides torque specs for every major fastener. In the Engine section, you’ll find valve clearance adjustments and head bolt torque sequences. For exact numbers, you need the manual – I’m not going to quote them here because that’s how mistakes happen. The point is Komatsu published these values for a reason, and the 2002 Service Manual has them in the Testing and Adjusting chapter. Don’t rely on internet forum numbers.

If you’re serious about keeping this machine running at factory spec, stop hunting for scraps of information. Get the real document. Access the Factory Manual from AutoRepairManuals and put it on your tablet or print it out. Your torque wrench and your wallet will thank you.