Description

Komatsu GD555-5, GD655-5, GD675-5 Workshop Manual

I’ve seen too many guys pull a head on a GD655-5 using a third-party manual that says “tighten to 80 ft-lb” and then wonder why the gasket leaks three days later. That mistake costs you a weekend and a set of head bolts. This Komatsu GD555-5, GD655-5, GD675-5 Workshop Manual is the factory print – the same binder the dealer techs flip through. It’s 1474 pages of what they don’t put in the aftermarket knockoffs.

Foreword and General Information: Safety and Handling

The manual opens with a safety notice and a standard tightening torque table that covers every thread on the machine. Page 1 gives the serial number range – GD555-55001 and up, GD655-55001 and up, GD675-55001 and up. That table on page 1 isn’t generic; it’s the actual Komatsu specs for bolts, nuts, and flange fittings. If you skip the “Precautions when carrying out work” section and go straight to the disassembly, you miss the warnings on handling electric equipment and hydraulic components. That’s how you get a hydraulic line in the face or short out a controller.

Specifications: Weight Table and Lubricants

Each model – GD555-5, GD655-5, GD675-5 – has its own specification drawing, weight table, and a table of fuel, coolant, and lubricants. The weight table tells you what your shop floor needs to handle. The lubricant table gives you the API grades and capacities in quarts and gallons. No guessing. If you’re doing a full fluid change, you need those numbers because overfilling a Komatsu transmission causes aeration and slipping. The manual spells it out in black and white.

1474 Pages of Factory Procedures

This isn’t a condensed manual. Every system – engine and cooling, power train, steering, brake, hydraulic, electrical – gets its own chapter under “Structure, function and maintenance standard.” The power train section alone covers the torque converter, transmission control valve, ECMV, main relief and TC relief valve, front axle, final drive (with and without differential lock), and tandem drive. Each subsection includes exploded diagrams, cross-sections, and hydraulic flow paths. If you need to diagnose why the transmission slips, you start with the transmission control valve and work through the pressure test procedures in the “Testing and adjusting” section.

Testing and Adjusting: Engine Speed and Valve Clearance

Chapter 30 (Testing and adjusting) has individual procedures for engine speed, intake air pressure, exhaust gas temperature, valve clearance adjustment, compression pressure, blowby pressure, engine oil pressure, fuel pressure, and cylinder cut-out test mode. The valve clearance adjustment procedure includes the order of rotation and the feeler gauge thickness in thousandths of an inch. Most aftermarket manuals tell you to “adjust until it feels right” – that’s how you burn a valve. The Komatsu manual gives a hard spec and the sequence.

Electrical System: KOMTRAX and Controller Circuits

The electrical system chapter covers the machine monitor, automatic shift control system, transmission controller, engine controller, KOMTRAX system, starting and stopping engine circuits, preheating circuit, sensor locations, engine power mode select circuit, and cooling fan control function. Wiring diagrams show pin numbers and wire colors. If you’re chasing a no-start condition and the aftermarket schematic has a different color code, you’re lost. This manual has the correct wire codes per Komatsu’s own standards, including the handling of connectors newly used for engines.

Standard Value Table: Engine and Machine

The standard value table beginning on page 20-1 covers both engine and machine specifications. It lists compression pressure limits, blowby pressure limits, oil pressure ranges, and hydraulic pressure settings for each system. For the power train, it gives the test port locations and the pressures you should see at stall and neutral. If you see a pressure reading outside the range, the troubleshooting section tells you which valve or pump to inspect. That’s the difference between a $20 manual and a $600 dealer visit.

Why OEM Beats Aftermarket

Aftermarket manuals often skip the “how to read the electric wire code” and “method of disassembling and connecting push-pull type coupler” sections. Those pages save you from breaking $200 connectors. The Komatsu manual includes a conversion table for imperial and metric units so you don’t get confused between ft-lb and Nm. I’ve seen techs strip a tandem drive bolt because the aftermarket manual had the wrong torque. This one doesn’t.

For related machines, check out the Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual”>WA65-5, WA70-5, WA80-5 workshop manual and the Komatsu WH609-1E0 WH613-1E0 WH713-1E0 WH714H-1E0 WH716-1E0 Workshop Manual”>WH609-1E0 through WH716-1E0 workshop manual. If you need the smaller PW class, the Komatsu PW95R-2 Workshop Manual – 520 Pages of Factory Specs”>PW95R-2 manual is also available.

For background on how a manual transmission works in these graders, Wikipedia has a solid overview: Manual Transmission”>manual transmission. The same basics apply to the Komatsu power train, but always rely on the factory specs for clearances and pressures: Manual Transmission”>manual transmission.

Frequently Asked Questions

Does this manual cover all three models (GD555-5, GD655-5, GD675-5) in one document?

Yes. One PDF file contains the complete workshop manual for all three models. The specification and standard value tables list each model separately where differences exist, but the structure and procedures apply across the series.

What serial numbers are covered?

GD555-55001 and up, GD655-55001 and up, GD675-55001 and up. If your machine has a lower serial number, some sections may differ – check the revision notice on page 2.

Are wiring diagrams included for the KOMTRAX system?

Yes. The electrical system chapter includes full wiring diagrams for the KOMTRAX system, engine controller, transmission controller, and machine monitor. Wire colors and connector pin numbers are shown. The “How to read electric wire code” section in the foreword explains Komatsu’s color and number standards.

Can I use this manual to overhaul the torque converter and transmission?

Yes. Section 10 (Structure, function and maintenance standard) covers the torque converter, transmission, transmission control valve, ECMV, and main relief valve with disassembly and reassembly procedures. The Standard value table on page 20-1 gives the clutch clearances and pressure settings you need for a correct rebuild.

If you are ready to stop chasing aftermarket garbage and get the real data, click the link and Access the Factory Manual.