Komatsu D20A-6, D20P-6, D20P-6A, D20PL-6, D20PLL-6, D20S-6, D20Q-6, D21A-6, D21E-6, D21P-6, D21P-6A, D21P-6B, D21PL-6, D21S-6, D21S-6A, D21Q-6 Shop Manual

This 493-page factory shop manual serves as the primary technical reference for the Komatsu D20 and D21 series bulldozers, covering the 60001-and-up serial number ranges. It provides a complete contents overview of the OEM documentation needed for shop maintenance and teardown planning. Servicing heavy machinery involves significant physical risks. Always review the factory-specified safety protocols inside the documentation before beginning any mechanical work to prevent injury or equipment damage.

• Covers 1992–2003 Komatsu models: D20A-6, D20P-6, D20P-6A, D20PL-6, D20PLL-6, D20S-6, D20Q-6, D21A-6, D21E-6, D21P-6, D21P-6A, D21P-6B, D21PL-6, D21S-6, D21S-6A, and D21Q-6
• Original OEM publication SEBM01040604 (dated 03-90(01)03381, Printed in Japan)
• Details structural breakdowns, assembly diagrams, and maintenance standards for the 4D95S-W-1 engine and powertrain

Component and System Coverage

This manual documents the exact engineering specifications required to service the 4D95S-W-1 engine. Technicians get a clear look at the powertrain, undercarriage, hydraulic systems, and electrical configurations. Chapters detail the structure and function of the Hydroshift transmission and planetary gear sets. This gives you the context needed for testing, adjusting, and overhauling the main and steering clutch assemblies. Comprehensive exploded-view diagrams are included. These cover the track group, bucket lift mechanisms for the S and Q variants, and radiator guard assemblies to speed up parts identification on the shop floor.

Specification and Reference Data

Engine timing and performance values are fully documented for both high and low idle ranges. Intake and exhaust valve clearances are specifically listed for cold-engine settings. To help mechanics maintain factory-grade tolerances, the text catalogs multi-stage torque values for the cylinder head assembly and injection pump components. Fluid capacities are provided for the engine oil pan, Hydroshift transmission case, and main clutch case. You will also find electrical circuit codes and wire-strand thickness classifications, making it easier to trace electrical faults effectively.