Description

Komatsu GD600R-1, GD650R-1, GD605R-1, GD655R-1, GD605A-1 Service Manual – The Real Deal

If you are wrenching on a Komatsu GD600R-1, GD650R-1, GD605R-1, GD655R-1, or GD605A-1 motor grader, you need the actual factory data. I have been a master technician for 28 years, and I have seen too many guys trust aftermarket PDFs that skip torque values or mislabel hydraulic ports. That is not a gamble you take on a machine that costs as much as a house. This is the OEM Service Manual – the same binder that sits in the dealer service bay. 764 pages of Komatsu internal documentation, not a third-party rewrite.

Engine and Drivetrain Coverage

This manual breaks down every major system. The engine section covers disassembly, reassembly, and all clearances. Transmission overhaul procedures are included for both the GD600R-1 and the larger GD655R-1. Need the charge pressure for the torque converter? Page 73 gives you the exact test procedure and the acceptable range in psi. That is not something a generic manual will tell you. I can tell you right now: if you try to set the clutch modulation without the factory spec, you will burn up the pack within 50 hours.

7 Systems Detailed – From Hydraulic to Electrical

Open the table of contents and you will see sections for the hydraulic system, steering, brakes, and even the air conditioner. The electrical section includes full wiring diagrams with connector pinouts. I have used these diagrams to chase down parasitic draws on a GD650R-1 that had me scratching my head for an hour. The wire colors and splice locations match the harness. Look up Manual Transmission if you want a general overview, but for the actual shift solenoid logic, you need the OEM schematic.

Every fluid capacity is listed in US quarts and gallons. Coolant, engine oil, hydraulic tank – they give you the fill procedure with venting steps. That is the kind of detail that prevents air locks and seal blowouts.

Who Needs This Manual?

If you own a fleet of GD600-1 series graders, this is your bible. Home garage enthusiasts who buy surplus equipment also need it – the wiring on these machines gets hacked by previous owners. Without the factory layout, you will spend weeks tracing circuits. I have a customer who brought in a GD605A-1 with a no-start condition. We found three wires swapped at the ignition relay. The OEM diagram on page 327 showed the correct routing, and we had the engine running in 20 minutes after the fix. That is the value of having the real document on your tablet or printed out.

Source Validity – Why This Is Not a Copy

This file is scanned from the original Komatsu publication SEBM023BA02. The watermark and revision history on page 00-2 show the update marks. Aftermarket manuals often omit the revised pages list, which means you could be using outdated specs. I have seen a mechanic snap a cylinder head bolt because he used the old torque value. Do not be that guy. The revision table here is intact, so you know exactly which pages have changed since the first printing.

Related manuals you might need for other Komatsu machines: Demag Komatsu H 285 S Service Manual – 544 Pages of Factory Specs, Komatsu WA430-6 Service Manual – 306-Page OEM Shop Manual, Komatsu WA470 2000 Service Manual – Factory Specs for Wheel Loaders. Also check Manual Transmission for general transmission theory if you are new to powershift transmissions.

Frequently Asked Questions

Does this manual cover the GD655A-1 too?

No. The GD655A-1 is not listed in the serial number range. This manual covers GD600R-1, GD650R-1, GD605R-1, GD655R-1, and GD605A-1 only.

What page has the brake bleeding procedure?

Page numbers are not provided in the product listing, but the brake system section is included. The manual uses a 00-xx and 01-xx numbering scheme. Look for the brake chapter under the chassis group.

Can I use this on a GD500 series grader?

No. The GD500 series is a different platform. This manual is specific to the GD600-1 series. Using it on a GD500 will give you wrong torque specs and hydraulic circuit details. You need the correct manual for that model.

I have a GD605A-1 that starts and then dies after 2 seconds. Will the wiring diagrams help?

Absolutely. That symptom is often a fuel shutoff solenoid circuit issue or an engine control unit power supply problem. The electrical section includes the starter and engine shutdown circuits. Check the wiring diagram for the ECM relay and verify voltage at the fuel solenoid. I have traced this exact fault on a GD605A-1 using the factory schematic – it saved me three hours of guesswork.

You have been warned: aftermarket manuals cost you time and parts. This is the real Komatsu documentation. 764 pages of factory-authorized repair procedures, torque specifications in ft-lb, and step-by-step removal/installation sequences. Stop wasting hours cross-referencing forums. Access the Factory Manual and get the job done right the first time.