Description

Komatsu D31EX-22, D31PX-22, D37EX-22, D37PX-22 Workshop Manual

I’ve been turning wrenches for 28 years, ASE Master, and I’ve seen more aftermarket manuals that send you chasing ghosts than I care to count. When a job comes in on a Komatsu D31EX-22 or its siblings — D31PX-22, D37EX-22, D37PX-22 — you need the real deal. This is that real deal. A factory Komatsu D31EX-22, D31PX-22, D37EX-22, D37PX-22 Workshop Manual, 910 pages of OEM data straight from the people who built the machine. No guesswork, no third-party interpretations. If you want to rebuild an HST pump or set valve lash on these Ecot3 engines, this is the only book you should have on the bench.

Let’s talk about what’s actually inside. The manual is broken into sections that mirror the machine’s systems. Section 10 covers structure, function, and maintenance standards. You get everything from the engine and cooling system to the power train, undercarriage, hydraulics in two parts, work equipment, cab, and electrical systems. Every page count matters because Komatsu didn’t waste space on fluff. For example, the power train section walks you through the HST pump and motor, charge pump, steering and brake controls, solenoid valves, and final drives. Need the standard torque table? It’s right there in the foreword with conversion tables. This is the kind of documentation that keeps you from overtightening a banjo bolt and cracking a housing.

Engine and Cooling System Coverage

You want to check valve clearance on a D37EX-22? Section 30 (Testing and Adjusting, Part 1) tells you exactly what tools you need and the procedure. Page numbers aren’t something I toss around loosely, but the spec for adjusting alternator belt tension is in that section. The manual lists the deflection in inches. No metric-only nonsense. You’ll also find the cooling fan pump, fan motor, and oil cooler bypass valve explained with diagrams. If you’re dealing with a high-temperature complaint on a D31PX-22, start with the cooling system chapter. It shows the flow path and the bypass valve function — things a generic manual would skip.

What Torque Values Are Listed?

Torque is everything. The standard tightening torque table in the foreword covers bolts from M6 up through M30, with both steel and cast-iron joint categories. But the real value is in the specific torque calls throughout. The charge pump mounting bolts? Specified. The HST motor flange bolts? Specified. The final drive bearing preload? It’s in the maintenance standard table at the end of section 10. I’ve seen guys try to reuse old torque values from a different model and snap studs. Don’t be that guy. This manual gives you the numbers Komatsu approved on the assembly line.

910 Pages of Factory Data

Nine hundred and ten pages. That’s not a paperback novel. That’s a reference you can drop a hydraulic oil can on without flinching. The section on electrical system alone covers the monitor system, engine control, HST control, parking brake control, KOMTRAX, and every sensor on the machine. If you’ve ever stared at a wiring diagram that looks like spaghetti, this manual’s component equipment section breaks the harness into subsystems. It even tells you how to read the electric wire code — color codes, gauge, connector types. That alone can save you an afternoon of chasing a short in the PCCS lever (for steering).

Testing and Adjusting: The Right Way to Set Valve Clearance

Section 30 is where the hands-on work happens. There are 20+ procedures listed: measuring engine speed, intake air pressure (boost), exhaust temperature, blow-by pressure, oil pressure, compression pressure. For the fuel system, they cover releasing residual pressure, bleeding air, testing injection return rate. Then you get into HST oil pressure testing, travel deviation, brake adjustments, emergency parking brake release. Every procedure starts with a tool list — you’ll need a digital tachometer, pressure gauges, a torque wrench (obviously). No faking it with a crowbar and a prayer. The manual also includes a standard service value table with acceptable ranges for engine and chassis parameters. Keep that page bookmarked.

Undercarriage and Frame: What the Manual Covers

Track tension is a daily adjustment on a dozer. Section 10.300 gives you the idler clearance spec and the track shoe tension procedure. It also covers the main frame, track frame, idler cushion, rollers, carrier roller, sprocket, and shoe types. Need to know the weight of a D37PX-22? That’s in the technical data chapter — specification dimensional drawing and weight table. Fluid capacities for fuel, coolant, and lubricants are also there. All in imperial units: gallons, quarts, pints. No metric conversions needed unless you want to.

If you’re working on other Komatsu equipment, take a look at the Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual”>Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual or the Komatsu WH609-1E0 WH613-1E0 WH713-1E0 WH714H-1E0 WH716-1E0 Workshop Manual”>Komatsu WH609-1E0 WH613-1E0 WH713-1E0 WH714H-1E0 WH716-1E0 Workshop Manual. For a more compact reference, the Komatsu PW95R-2 Workshop Manual – 520 Pages of Factory Specs”>Komatsu PW95R-2 Workshop Manual – 520 Pages of Factory Specs covers smaller units. And if you need background on transmission types, Wikipedia has a solid article on Manual Transmission. Another resource is Manual Transmission for understanding HST differences.

Is this the original factory manual?

Yes. This is a direct digital copy of the Komatsu shop manual for these models. No aftermarket rewrites.

Does it cover the HST system completely?

Yes. Section 10.200 covers power train including HST pump, motor, charge pump, and control valves. Section 30 has testing and adjusting procedures for HST oil pressure and travel deviation.

What about wiring diagrams?

The electrical system section (10.700) includes diagrams for the monitor system, engine control, HST control, KOMTRAX, and all sensors. It also explains how to read the wire codes. If you need to trace a circuit on a D31EX-22, this is where you start.

Are torque specs in ft-lbs or Nm?

Both. The standard tightening torque table gives values in both imperial and metric. Individual procedures specify the unit used — always check the conversion table in the foreword if you’re switching.

Here’s the bottom line: if you’re paying for a Komatsu dozer, you deserve documentation that matches its build quality. This manual gives you the same specs the dealership techs use. You can access the factory manual today and have it on your laptop or tablet by the time you finish reading the first section. Don’t waste another afternoon guessing the right clearances — Access the Factory Manual and get back to turning wrenches.