Operation CHARM: Car repair manuals for everyone.

Transmission and Drivetrain: Testing and Inspection

VEHICLES WITH ANTI-LOCK BRAKES (ABS)

WARNING: Do not attempt to test ABS function on a dynamometer

FOUR WHEEL DYNAMOMETERS

NOTE: Before testing a vehicle on a four wheel dynamometer disconnect the valve relay.
^ The ABS function will not work, the ABS warning light will illuminate.
^ Normal braking will be available.

Provided that front and rear rollers are rotating at identical speeds and that normal workshop safety standards are applied, there is no speed restriction during testing except any that may apply to the tires.

TWO WHEEL DYNAMOMETERS

IMPORTANT: Use a four wheel dynamometer for brake testing if possible.

NOTE: ABS will not function on a two wheel dynamometer. The ABS light will illuminate during testing. Normal braking will be available.

^ If brake testing on a single rig is necessary it must be carried out with propeller shaft to the rear axle removed, AND neutral selected in BOTH main and transfer boxes.
^ If checking engine performance, the transfer box must be in high range and drive shaft to stationary axle removed.