Komatsu HD325-6 (2WD), HD325-6W (4WD) & HD405-6 Off-Highway Truck 2001 Shop Manual (P/N SEBM015108)

• Supported Models: Covers Komatsu HD325-6 (2WD), serial 5680 and up; HD325-6W (4WD), serial 5706 and up; and HD405-6, serial 1055 and up.
• Publication: Komatsu shop manual SEBM015108, February 2001 print, supplied as a 1,320-page PDF covering specifications, structure and function, testing and adjusting, disassembly and assembly, maintenance standards, and circuit diagrams.
• Engine / Serial Break: SAA6D140E-2 applies to HD325-6 5680-6000, HD325-6W 5706-6000, and HD405-6 1055-2000. SAA6D140E-3 begins at 6001, 6001, and 2001 respectively. Both versions are listed at 15.23 L displacement, 364 kW (488 HP) net at 2,000 rpm, and 2,167 Nm at 1,400 rpm.

Component Breakdown and Workshop Value

The chassis coverage goes well beyond routine maintenance. The manual identifies the TCA-48-10A 3-element, 1-stage, 2-phase torque converter with wet multi-disc lock-up clutch and the fully automatic, electro-hydraulically controlled TORQFLOW planetary transmission with F7/R1 ranges. Structural and repair sections cover the output shaft/flywheel connection, ECMV (Electronic Control Modulation Valve), differential, rear final drives, front and rear brakes, steering linkage, hoist system, and hydropneumatic suspension cylinders. General reference tables also give standard tightening torques for metric fasteners, flared nuts, split-flange bolts, and O-ring boss joints.

The HD325-6W is treated as a distinct 4WD configuration rather than as a footnote to the 2WD truck. Its coverage includes the front-drive hydraulic circuit, front-drive piston pump and motor, front final-drive clutch/carrier, front drive shaft, travel motor, front-drive ECMV, 4-wheel-drive controller, steering-angle sensor, high-pressure oil-pressure sensor, clutch-pressure sensor, and wheel-speed sensor. The automatic suspension section documents Soft, Medium, and Hard damping modes together with the controller and sensor logic used to change modes.

Serial-specific data is carried into the testing and fluid sections. For the earlier serial group, the brake-cooling gear pump is rated at 472 L/min at 2,100 rpm; the later group lists 450 L/min at 2,000 rpm. Fluid tables also distinguish the engine changes: the early engine oil pan is 41 L specified / 37 L refill with a 106 L specified cooling-system capacity, while the later engine lists 56 / 52 L and 89 / 89 L. Chassis references include a 195 L transmission case (including the front-drive case where applicable), 165 L hydraulic tank, 50 L differential case, and 17 L per final drive.

Factory Repair and Diagnostic Procedures

The factory procedures include work that is commonly sent to a heavy-equipment repair shop when the correct fixtures, gauges, and setup data are not available:

• torque converter/transmission removal, separation, overhaul and reassembly; ECMV removal and internal service; transmission clutch-pressure testing and torque-converter stall testing
• differential and rear final-drive overhaul, plus HD325-6W front final-drive clutch/carrier, front-drive brake and shaft work
• front/rear brake service, parking-brake caliper and chamber work, slack-adjuster service, brake-pressure testing, and brake-circuit bleeding
• front and rear suspension-cylinder removal, disassembly, assembly, nitrogen charging/adjustment, variable damping selector valve service, steering/hoist pump and valve work, steering and hoist cylinder repair, and dump-body removal/installation

Engine-related procedures include valve-clearance adjustment, compression and blow-by measurement, boost and oil-pressure checks, fuel-injection timing on the earlier build, common-rail fuel-system checks on later machines, plus removal/installation coverage for the injection pump, turbocharger, nozzle holders, cylinder head, and complete engine assembly. For detailed internal engine overhaul information, Komatsu directs the reader to the separate 6D140-2 or 140-3 Series Engine Shop Manual; this chassis publication does not replace that engine manual.

Troubleshooting coverage includes connector locations and pin tables, monitor/service-code data, controller self-diagnostics, and dedicated sections for engine, transmission, suspension, payload meter printer/card systems, automatic retarder speed control, hydraulic/mechanical systems, monitor panel, and the later electronic engine controller. The factory publication also identifies test and repair tooling by part number, including the 799-203-8001 multi-tachometer, 799-101-5002 hydraulic tester, 792-610-1100 suspension pump/joint kit, 792-610-1200 gas-charge tool kit, transmission clutch-pressure assemblies 792-415-1200 and 792-415-1100, and the 790-101-2102 puller with 790-101-1102 30-ton pump for output-shaft work.

Specification Highlights and Safety Reference

Circuit coverage includes the torque-converter/transmission/brake-cooling hydraulic circuit, the HD325-6W front-drive hydraulic circuit, the air circuit diagram, separate inside- and outside-cab electrical circuit diagrams for the applicable serial groups, the automatic suspension system circuit, and the A/C refrigerant circuit. The testing tables provide concrete limits: torque-converter main relief pressure is 3.285 MPa at low idle and 3.58 MPa at high idle, steering relief is approximately 19.61 MPa, and hoist relief is 20.59 ± 0.49 MPa.

Several repair cautions are assembly-specific. Forcing the torque converter into the transmission can damage its seal ring. During final-drive and brake work, the manual calls for the specified holding tools and careful handling to protect floating seals. After steering-cylinder or piping repair, trapped air is specifically identified as capable of damaging the piston seal through compression and combustion.

For work around a raised dump body, pressurized steering/hoist circuits, suspension cylinders, brake systems, or the later common-rail fuel circuit, follow the manual's machine-support, pressure-release, and electrical-isolation precautions before starting hands-on repair.