Komatsu WA320-3 Avance Wheel Loader Shop Manual (P/N SEBM006006 / U41903)

• Two Komatsu factory shop manuals for the WA320-3 are included: SEBM006006 / U41903, 1997 Avance edition, for serial numbers 50001 and up (845 PDF pages), and VEBM450104, printed 03/2000, for WA320H20051 and up (962 pages). Together they provide 1,807 pages of model-specific chassis, testing, repair, and maintenance-standard data.
• The 50001-up volume separates 50001–52999 and 53001-up general assembly, specification, and weight data. The H-series volume adds important serial breaks, including the engine change at H20561 and main-control-valve versions through H20343, H20344–H20710, and H20711-up.
• Engine identification is configuration-specific: the 50001-up machines use the Komatsu S6D108 7.15 L six-cylinder turbo diesel; H20051–H20560 machines use the Cummins 6CT8.3 8.27 L engine; H20561-up machines use the Komatsu S6D114E-1 / 419 8.27 L engine.
• Factory diagrams cover the driveline, hydraulics, brakes, steering, electrical controls, and machine monitoring. Representative titles include Transmission Hydraulic Circuit Diagram, Brake Hydraulic Circuit Diagram, Work Equipment Hydraulic Circuit Diagram, Kick-Down Electric Circuit Diagram, Connector Pin Arrangement Diagram, and the H-series Wiring Diagrams.

Technical Walkthrough and Component Data

The drivetrain chapters go well beyond exploded views. They explain the Komatsu TCA32-8A three-element, one-stage, single-phase torque converter, the 4-forward/4-reverse modulation-type transmission, six hydraulically actuated clutch functions, transmission control valve, pilot reducing valve, main relief valve, priority valve, quick-return and accumulator circuits, drive shafts, torque-proportioning differential, final drives, and wet-disc parking brake. Flow descriptions show what happens through the clutch and converter circuits during gear selection and pressure modulation, which is useful when a repair problem is hydraulic rather than mechanical.

Hydraulic and steering identification is equally specific. The manuals list the combined hydraulic/steering/switch/PPC pump as SAL(3)71+(3)32+(3)32+(1)20, with delivery shown as 165+77+77+49 L/min and a 20.59 MPa set pressure for both work-equipment and steering circuits. Steering coverage runs through the priority valve, orbit-roll steering valve, cushion valve, steering cylinders, and emergency-steering functions. The H-series lubricant data also distinguishes standard TPD axle configurations from multi-disc limited-slip axle versions, an important difference when selecting axle lubricant and repair information.

Testing, Repair, and Diagnostic Scope

Factory procedures cover jobs normally handled as shop work: torque converter/transmission removal and installation, transmission and clutch-pack overhaul, transmission control and modulation valve repair, front and rear axle removal, differential and axle-housing overhaul, center-hinge-pin work, steering-valve disassembly, brake-system testing and bleeding, hydraulic/steering pump removal, main-control-valve repair, hydraulic-cylinder overhaul, and work-equipment removal and installation. Engine-related chassis procedures cover valve-clearance checks, compression and blow-by testing, injection-timing checks, turbocharger and nozzle-holder work, cylinder-head service, and complete engine removal/installation.

Testing sections provide standard and permissible values for stall speed, converter and transmission pressures, steering pressure, brake pressure and disc wear, work-equipment relief pressure, PPC pressure, hydraulic drift and cycle times, bucket positioner, boom kick-out, speedometer/main-monitor adjustment, electrical sensors, wiring continuity, and accumulator checks. Factory tool numbers are called out rather than left generic; examples include 799-101-5002 analog hydraulic tester, 793-520-1803 brake test kit, 793-463-1100 boom-drop prevention stopper, and 793-415-1160 / 1170 / 1130 piston-seal holders for the transmission clutch groups.

System Identification and Reference Values

The 50001-up S6D108 specification lists 7.15 L displacement, 121 kW (163 HP) at 2,380 rpm, and 647 Nm at 1,600 rpm. In the H-series manual, the Cummins 6CT8.3 is rated at 124 kW (168 PS) at 2,350 rpm and 648 Nm at 1,600 rpm, while the H20561-up S6D114E-1 / 419 is rated at 124 kW (168 PS) at 2,380 rpm with 671 Nm maximum torque. Fluid data includes a 221 L fuel tank, 42 L transmission capacity with a 40 L top-up quantity, and a 165 L hydraulic system with a 116 L top-up quantity in the H-series specification. Air-conditioning data identifies R134a refrigerant at 1,500 g with 150 cm³ PAG oil. Component-specific tightening values continue through the repair sections; one example is the 549 ± 59 Nm transmission coupling mounting torque.

Several assembly notes are worth knowing before opening a major component. During transmission housing assembly, the input-shaft spline must mesh correctly and the shaft seal rings must be protected; careless alignment can damage the rings. The parking-brake piston seals are directional and must not be twisted, and the cover oil seal is specifically protected from shaft contact during assembly. Center-hinge bearings and spacers are clearance-matched sets, so mixing the bearing/spacer combination or omitting the spacer can put hinge-bearing fit out of specification and lead to premature bearing damage.

The 50001-up chassis manual identifies the S6D108 installation but directs full engine details to the separate 108 Series Engine Shop Manual. It still contains substantial engine-related testing, external-component repair, cylinder-head work, and engine removal/installation, but it is not a complete internal S6D108 engine-overhaul volume.

These repair procedures involve stored hydraulic and brake pressure, heavy driveline components, and raised work equipment. Follow the manual's pressure-release, blocking, lifting, and electrical-isolation precautions before beginning structural or hydraulic repair work.