Description

Komatsu GD555-3C, GD655-3C, GD675-3C 2006 Workshop Manual

If you’re working on a Komatsu GD555-3C, GD655-3C, GD675-3C 2006 Workshop Manual and you don’t have the factory book on the bench, you’re flying blind. I’ve torqued enough head bolts to know that one wrong spec means a comebacks or a blown gasket. This 713-page OEM manual is what Komatsu issued for the GD555-3C (SA6D102E-1 or SAA6D102E-2 engine), GD655-3C, and GD675-3C (S6D114E-1, SA6D114E-1, or SAA6D114E-2 engine). It’s the same binder the dealer techs use. No aftermarket condensation, no “recommended” values – only factory printed numbers.

Transmission Valve: What the Manual Covers

Inside section 10 (Structure, Function and Maintenance Standard) you get the full breakdown of the Transmission Valve, the ECMV (Electronic Control Modulation Valve), and the Main Relief Valve. The manual walks you through the hydraulic piping for the transmission and differential lock pump. If you’ve ever had a grader that won’t shift or that hunts for gears, the troubleshooting charts in section 20 will save you a full day of head-scratching. Need clutch oil pressure? That’s in the Standard Value Table – page 20-1 gives you the numbers for engine, chassis, and electrical system. Don’t guess; use the factory chart.

Torque Specs and Fluid Capacities

One thing that drives me nuts is a mechanic using a generic torque chart for hydraulic fittings. This manual lists every fastener torque for the Transmission, final drive, tandem drive, and steering valve. It also includes the exact fuel, coolant, and lubricant selection table from the OEM. You want to know the capacity for the transmission? It’s in the Specifications section under 01 General. The manual even tells you the weight table for each model, so you can plan your lift points. Nothing worse than finding out your jack is undersized after you’re halfway through a job.

Testing and Adjusting Procedures

Section 20 is where the real work gets done. There’s a full Testing and Adjusting chapter that covers everything from measuring blowby pressure to flushing the torque converter and transmission circuit. The manual gives you the tool list for testing – I counted 14 specific tools they expect you to have, like a tachometer, pressure gauge set, and a digital multimeter. If you’re bleeding air from the brake piping (page 20-something), the step order is critical. Skip one step and you get a soft pedal that’ll kill someone. The manual doesn’t let you skip. It also includes the procedure to charge nitrogen gas for the brake and work equipment accumulator – that’s a safety issue right there.

Does This Manual Cover the Fuel System?

Yes, but indirectly. The GD555-3C uses the 102 Series engine, and the GD655/675-3C use the 114 Series. The manual clearly states that for engine details you need the separate engine shop manuals. What it does cover for fuel is the injection pump drive and governor linkage adjustments – see the Accelerator Control Linkage section. The Fuel section in the standard value table gives you the blowby pressure specs and exhaust color measurement procedure. If you’re chasing a low-power issue, start with the fuel system diagnostics described in section 20. The manual also includes the diode checking procedure and how to memorize idle and full position – critical for electronic controlled engines.

3 Reasons to Choose OEM Documentation

First: torque values. Aftermarket manuals often round numbers or copy old editions. This Komatsu manual is the original print from 2006, with revision marks and page corrections listed right on the cover page. Second: the wiring diagrams are factory color-coded. The Connector Arrangement Diagram and message center error codes (section 20 troubleshooting) are exact – you can trace from the sensor to the controller without guessing. Third: the valve clearance specs. Adjusting a Valve on the S6D114-1 requires a specific sequence that only appears in the OEM book. Third-party versions leave out the “initial learning method for transmission controller” because it’s too model-specific.

Audience Fit: DIY vs. Professional

This manual is written for a tech who knows their way around a torque wrench but needs the specifics. If you’re a home garage enthusiast working on a grader, you need this because the Transmission hydraulic system is not forgiving. The manual assumes you have basic tools but doesn’t assume you know the machine. For the pro, it saves billable hours – the troubleshooting sequence is logical, and the failure codes (T-1, T-2, etc.) are listed with the exact test points. I’ve used it to diagnose a failed ECMV in under an hour because the voltage readings were in the chart. Pair this with the Komatsu GD555-3C Service Manual – 271-Page OEM Shop Manual for a quick reference, or grab the Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual if you have a wheel loader in the shop too. For more on the Manual Transmission fundamentals, the theory section here references external resources, but the actual adjustments are all inside.

Can I use this manual for the engine alone?

No. Engine details are in the separate 102 and 114 Series Engine Shop Manuals.

What serial numbers does this cover?

GD555-3C serial 50001 and up, GD655-3C 50001 and up, GD675-3C 50001 and up. There are also separate sections for priority valve serial 51001 and up. If your machine falls outside that range, double-check with your distributor – the manual lists revisions by serial number on page 00-2-1.

One last thing: this manual includes the air conditioner section (if equipped), the blade float device, and the circle rotation motor. Don’t throw away your time on aftermarket PDFs that mislabel hydraulic ports. Access the Factory Manual and keep it on your tablet or print the pages you need. Trust the paper that came from Komatsu, not some copy shop. For the Komatsu WH609-1E0 WH613-1E0 WH713-1E0 WH714H-1E0 WH716-1E0 Workshop Manual and other OEM books, check the related section. If you’re still reading this, you know you need the real thing. Get it.