WORKHORSE CUSTOM CHASSIS
Service Manual
2007 W Series
SECTION
7.2
PAGE
476
Automatic Transmission – Allison
2007 W Series Chassis
© 2006 Workhorse Custom Chassis — All Rights Reserved
WSM082106
LOW MAIN LINE PRESSURE IN ALL RANGES
Condition
Action
Incorrect fluid level
Correct the fluid level. Refer to Transmission Fluid Checking Procedure.
Plugged or faulty suction filter
Clean or replace the oil suction filter element. Refer to Oil Pan
Replacement.
Main pressure regulator valve sticking
Overhaul the control module assembly.
Leaking solenoids in control valve body assembly
Replace the solenoids. Refer to Control Valve Solenoid Replacement.
Main pressure regulator valve spring weak, broken, or missing
Inspect the spring and replace, if necessary.
Control module body leakage - separator plate not flat, loose con-
trol valve body bolts
Replace or rebuild the control module assembly. Care should be taken when
removing and labeling shift springs.
Faulty or incorrect fluid pressure gage
Repair or replace the gage.
Oil pump worn or damaged
Replace or rebuild the oil pump.
Leak in suction circuit
Inspect the suction circuit for leaking seal, gasket, or mating surface.
LOW MAIN LINE PRESSURE IN SPECIFIC RANGES,
NORMAL PRESSURE IN OTHER RANGES
Condition
Action
Seal leak
Replace the seals that are causing low pressure in a particular range.
