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TM 5-3805-292-10
OPERATOR MAINTENANCE
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THEORY OF OPERATION
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INTRODUCTION
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The M400W and M400T Skid Steer Loaders (SSL) consist of the following functional systems: engine, powertrain,
chassis, electrical system, hydraulic system, and work tool attachments.
This work package explains how the systems and components of the machine work together. A functional
description is provided for each major component and system.
ENGINE
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1. General. The machine is equipped with a 3.2 liter, 4-stroke turbocharged Case F5C diesel engine, with
4 cylinders, generating 74 hp (55kW) (gross) at 2,500 rpm.
2. Fuel System. A flange-mounted, fuel injection pump is mounted in the cylinder block and operated by
timing gear.
3. Cooling System. A belt-driven centrifugal water pump circulates coolant via the internal water passages. The
coolant is radiator cooled and temperature controlled by a conventional thermostat.
4. Lubricating System. An oil pump located in the center of the idler gear sends lubricating oil through a relief
valve to the main oil gallery and then through a bypass oil filter. The rockers are fed through an oil pipe from
the main oil gallery to the cylinder head.
POWERTRAIN
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1. Hydrostatic System. The engine provides power to two hydrostatic pumps, one driving each side of the
machine. Each hydrostatic pump drives a corresponding hydrostatic motor. The M400W motor drives both
axles. The M400T motor drives the track directly.
2. Axles. Consist of one-piece, forged induction-hardened high carbon steel.
3. Tracks. The M400W is equipped with steel tracks over rubber tires. The M400T is equipped with steel-
embedded rubber tracks.
4. Parking Brakes.
a. The parking brakes are spring applied, hydraulic release (SAHR) disc.
b. Parking brakes are engaged in three ways:
On/Off Brake button on instrument panel is pressed;
Right hand control handle button is pressed; or
Seat belt is unbuckled and operator gets off seat or engine is stopped.
CHASSIS
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1. The machine comes with a radial loader arm design and mechanical attachment coupler.
2. The machine has a Rollover Protective Structure/Falling Object Protective Structure (ROPS/FOPS) cab with
heater and air conditioning, which allows for all-weather operation.
3. The air conditioning system uses an evaporator core to exchange heat energy inside the cab. The A/C
compressor circulates R134 through the A/C components.
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