Description

Komatsu D31EX, D31PX, D37EX, D37PX, D39EX Operators Manual

I’ve watched guys burn up an undercarriage on a D37 because they thought “close enough” on a track adjustment. Then they blame the machine. If you’ve ever pulled a printed-off photocopy from some third-party site and wondered why the coolant capacity was wrong, you know exactly why you need an original factory **Komatsu D31EX, D31PX, D37EX, D37PX, D39EX Operators Manual** in the cab. This is the same 256-page document that came with the machine when it left the factory. It tells you where the serial number plate is (page 1 shows the exact serial number ranges for each model), how to interpret the check monitor system, and how to safely start the engine in cold weather. No guesswork, no translation errors.

Safety Information: Noise, Vibration, and Labels

Page 5 gives you the signal words – WARNING, CAUTION – and explains exactly what they mean on this machine. The safety section covers noise exposure, vibration limits, and the location of every safety pictogram on the bulldozer. If you’re sending a new operator into a D31PX, make them read this section before they touch the levers. The manual also includes general precautions for operation and maintenance: battery handling, towing, transportation. One thing I see all the time is guys jumping a dead battery without reading the battery precautions. That’s how you get an arc flash. This manual tells you the sequence for booster cables – step by step, no shortcuts.

Necessary Information: PIN, Serial Plates, and Service Meter

You need the machine serial number to order parts. This manual shows you exactly where the Product Identification Number (PIN) plate and engine serial number plate are located. It also tells you where the service meter is – critical for tracking maintenance intervals. There’s a table to enter the serial number and distributor info so you keep your own records. That’s the kind of detail that gets skipped when you access a bootleg PDF from a forum. The official document is laid out to be used in the field, not just read once.

Operation Section: From Starting Engine to Troubleshooting

This is the meat of the manual. It covers the check monitor system, all switches, control levers and pedals, the fuse layout, and even the cup holder. If you need to know how to use the maintenance mode on the front panel, it’s in here. The operation chapter walks you through a full walk-around check, starting the engine normally and in cold weather, warm-up procedures, shifting gears, steering, and dozing techniques. There’s a whole section on long-term storage: what to do before, during, and after. Troubleshooting includes what to do after running out of fuel, how to tow the machine (when the engine starts and when it doesn’t), and how to jump-start with booster cables. That troubleshooting section alone can save you a tow bill if you read it first.

256 Pages of Factory Specs – What’s Inside?

256 pages covers everything from the foreword to the index. You get specifications for the engine, attachments, and options. The manual uses international standard (SI) units but also gives the imperial equivalents in curly brackets – so if you work in inches and pounds, you’re covered. The table of contents is broken into Foreword, Safety, Operation, Maintenance, Specifications, Attachments & Options, and Index. The Manual Transmission section isn’t in this operators manual – that’s covered in the service manual – but the operation and maintenance sections are complete for daily use. For deeper repairs, you’ll want the Komatsu D31 D37 2004 Workshop Manual or the Komatsu D31EX D31PX D37EX D37PX D39EX 2007 Workshop Manual. This operators manual is for the guy running the machine and doing basic maintenance.

Cold Weather Operation and Long-Term Storage

If you work in places where the temperature drops below freezing, this chapter is worth the price alone. It covers precautions for low temperature, what to do after completing work in cold weather, and what to do after cold weather passes. Long-term storage has three sub-sections: before storage, during storage, and after storage. I’ve seen machines sit for six months and come back with corroded injectors because nobody followed the storage procedure. The manual tells you how to prepare the engine, the cooling system, and the battery for months of inactivity. Follow it, and that machine starts on the first crank when you need it again.

Why a Factory Operators Manual Beats Aftermarket Copies

Aftermarket operators manuals are often reprints of older editions with missing pages or incorrect torque values. This is the original OEM document – same as what Komatsu shipped with the machine. The wiring diagrams, the check monitor logic, the maintenance intervals – all verified by the factory. If you try to use a generic manual for a D39EX, you might not get the correct accumulator pressure release procedure. That’s a safety hazard. The factory manual lists the exact method for releasing pressure in the operating circuit on machines equipped with an accumulator. You don’t guess, you don’t skip steps. For a full service manual with engine rebuild specs, see the Komatsu D31EX, D37EX, D39EX, PX-21 Service Manual – OEM Factory Specs. But for daily operation and proper maintenance, this operators manual is the one you keep in the door pocket.

Frequently Asked Questions

Does this manual include torque specifications for the engine?

No. This is an operators manual, not a service manual. Torque specs for major engine components are in the service manual. This manual covers operation, daily maintenance, and safety.

Can I use this manual to rebuild the transmission or final drives?

You’ll need the service manual for that. This operators manual covers inspection and adjustment of the undercarriage (track tension, sprockets, idlers) and tips for longer undercarriage life, but it doesn’t include disassembly procedures or internal tolerances. The transmission is a powershift unit – the service manual has the clutch pressure specs and hydraulic circuits. For basic operation and preventive maintenance, this is all you need. For tear-down work, pair it with the factory service manual. If you want a reference on Manual Transmission fundamentals, that’s a separate topic – this machine uses a hydrostatic or powershift transmission depending on the model.

You operate a Komatsu D31EX, D31PX, D37EX, D37PX, or D39EX – you need the manual that came with it. Keep it in the cab, read the safety warnings, and follow the maintenance schedule. That’s how you keep the undercarriage alive and the engine running for 10,000 hours. Access the Factory Manual and put it to work.