Komatsu D41-6: engine serials, steering and blades

D41 engine plates and blade arrangements

A D41-6 badge does not identify one engine installation. Komatsu's SEBM007009 covers B20001–B40000 and a separate 50001-and-up sequence with the S6D102-1. SEBM028803 starts at B40001 and specifies the aftercooled SA6D102E-2.

These are different serial ranges. The latter manual rates its engine at 82 kW at 2,300 rpm; the earlier specifications use 2,400 rpm. Match the plate before ordering engine parts.

The C-labelled reference entries below remain identifiable, but the manuals do not establish that C is a universal identifier for the later engine.

The later shop manual also separates steering from inching. Moving the steering lever a little releases part of the clutch on that side; moving it fully releases that clutch and applies the corresponding brake. Inching changes pressure to the forward or reverse transmission clutch.

A weak turn and poor inching therefore need different observations. Brake-pedal operation and the safety lever have their own connections; the safety lever also operates the parking-brake valve. None of those controls is an engine-speed setting.

The early manual's hydraulic explanation gives blade float a specific meaning: the lift-cylinder circuit connects to drain while the pump circuit stays separated, permitting tilt or angle operation. Float is not simply a lower command. Its track schedule specifies 171.5 mm pitch, with different E and P shoe counts.

The earlier seventy-inch entries are unit errors, retained in the correction history. Track gauge measures the spacing between the tracks; it cannot substitute for width across the shoes.

Komatsu's European EESS015902 brochure distinguishes ordinary blade angling from the transport position. The super-angle setting brings the blade within the track-shoe envelope; the wide P blade has its own restriction. Identify the blade, not just the tractor.

Its cooling fan is hydraulically driven and reversible from the cab for radiator cleaning. That fan does not make the travel transmission hydrostatic: the same brochure describes Hydroshift as a damper and planetary transmission. Gull-wing engine doors and a centralized pressure-test location give access to different service points, so a radiator-cleaning demonstration says nothing about transmission clutch pressure.