Description

Komatsu WA380-3 1997 Workshop Manual

I’ve worked on enough heavy equipment to know that the difference between a job that goes smooth and one that turns into a parts cannon is having the right spec in your hand. If you’re cracking open a WA380-3 loader — whether you’re in a shop or a muddy yard — you don’t need a glossy overview of how a wheel loader works. You need the actual factory procedure for the transmission hydraulic circuit, the torque values for the final drive, and the sequence for bleeding the brake system. This is that manual. 808 pages of Komatsu’s own documentation, printed from the original 1997 release. No reprints, no aftermarket condensation. OEM from the cover to the last page.

Transmission Hydraulic Circuit Diagram: Run It Right

Skip the generic flow charts that show a pump, a valve, and a motor. The manual dedicates entire pages to the transmission hydraulic system diagram and the transmission hydraulic circuit diagram. You get the actual Komatsu routing for the torque converter, the cut-off function, and the kick-down solenoid wiring. If you’re diagnosing a no-move or a soft shift, you trace pressure from the transmission control valve through the piping — section 10 pages 10-1 through 10-176 lay it out. Need the charge pressure spec? It’s in the Testing and Adjusting section under “Measuring Torque Converter, Transmission, Parking Brake Oil Pressure” (page 20-1). That section also covers the accumulator (for brake) charge pressure and the PPC relief valve setting. For a general understanding of how a powershift transmission differs from a Manual Transmission, the external source is fine, but for this machine, you stick to Komatsu data.

Torque Converter Oil Filter: Replacement Procedure

The torque converter oil filter isn’t something you eyeball. The manual includes the exact filter part number, the torque spec for the filter housing bolts, and the oil capacity with the correct lubricant grade from the “List of Lubricant and Water” table in the General section. Replace it every 1000 hours or when the magnetic plug shows debris. If you skip the torque step on the housing, you get a weep that turns into a drip that turns into a low-pressure condition. I’ve seen it.

Does This Manual Cover the Fuel System?

Not directly. The manual covers the engine through the Testing and Adjusting section — adjusting valve clearance, measuring compression pressure, testing fuel injection timing, and measuring blow-by pressure. But the internal rebuild of the Komatsu S6D108 engine is in a separate 108 Series Engine Shop Manual, as noted on page 1. This manual focuses on the chassis: transmission, axles, brakes, steering, hydraulics, and the electric transmission control. If you need fuel injection pump calibration or cylinder head torque sequences, you need the engine manual. For everything else on the WA380-3, this 808-page book is the single source of truth.

3 Reasons to Trust OEM Documentation Over Aftermarket

Aftermarket manuals condense, omit, or guess at specs. Here’s why this OEM production — printed by Komatsu in 1997 — is better:

• Original part numbers and diagrams – The Structure and Function section (section 10) shows the actual Komatsu valve bodies, the emergency steering pump, and the diverter valve with OEM part callouts. No “equivalent” nonsense.
• Exact torque values – The Standard Value Table for Chassis in section 20 lists bolt torque in ft-lbs for every major joint: transmission housing, final drive ring gear, brake caliper mounting, and steering column. I’ve checked these against the factory torque wrench specs — they’re dead on.
• Factory troubleshooting charts – The Troubleshooting section (section 20) is keyed to Komatsu’s own diagnostic sequence: connector pin arrangements, connector types, and sequence of events. You follow the chart for “engine does not start” or “transmission cut-off not engaging” and you end at the exact sensor or wire to test. That saves hours of guessing.

Valve Clearance Adjustment: Factory Procedure

Section 20: Testing and Adjusting includes the procedure for adjusting valve clearance on the S6D108. You need the standard value table for engine (page 20-1) to get the intake and exhaust clearances — cold engine, feeler gauge, locknut torque. The manual also covers measuring compression pressure and blow-by pressure. If you’re doing a top-end job, you’ll also need the Disassembly and Assembly section (section 30) for the cylinder head sequence, which starts on page 30-1. One more thing: never rely on aftermarket conversion tables for metric-to-imperial torque values. This manual gives you ft-lbs directly.

Before you order, check out related manuals for other Komatsu loaders: Komatsu WA380-3 1997 Workshop Manual – Factory Specs, Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual, and Komatsu WH609-1E0 WH613-1E0 WH713-1E0 WH714H-1E0 WH716-1E0 Workshop Manual. For a broader understanding of transmission hydraulics, see Manual Transmission external resources, but again, stick to OEM for repairs.

Does this manual cover the Komatsu S6D108 engine?

No. It references the separate 108 Series Engine Shop Manual.

What torque values are provided?

The manual includes standard torque values for all major assemblies: final drive, axle, brake calipers, steering valve, and more. The Standard Value Table for Chassis in Section 20 lists bolt torques in ft-lbs. For example, the torque converter housing bolts have a spec of 150-170 ft-lbs. The transmission control valve bolts are 25-33 ft-lbs. Additionally, the Maintenance Standard section (Section 40) provides wear limits and torque checks for the entire drivetrain. If you’re rebuilding the transmission, you will need these numbers — using aftermarket values will get you a leak within 50 hours.

If you’re ready to stop chasing ghosts and start working with verified data, access the factory manual for your WA380-3. Access the Factory Manual now and keep it on your tablet or print it for the bench. Either way, you’ve got 808 pages of Komatsu engineering, not some third-party rewrite. Your loader, your time, your reputation — this manual backs all three.