WORKHORSE CUSTOM CHASSIS
Service Manual
Automatic Transmission – Allison
2007 W Series
© 2006 Workhorse Custom Chassis — All Rights Reserved
SECTION
7.2
PAGE
479
2007 W Series Chassis
WSM082106
LOW STALL SPEEDS (STALL IN RANGES 1-6)
Condition
Action
Engine not performing efficiently
• Plugged or restricted injectors
• High altitude conditions
• Dirty air fi lters
• Incorrect fuel/valve timing
• Throttle linkage broken or not adjusted correctly
• Electronic engine controls condition
Refer to the Engine section of this manual.
The following specific sections should be helpful in defining the condition:
• Refer to Diagnostic System Check - Vehicle .
• Refer to Symptoms - Engine Mechanical in Engine Mechanical - 8.1L.
Stall speeds of 33% of normal implies freewheeling stator
Replace the converter assembly. Refer to Torque Converter Replacement .
Engine smoke controls
Compare lugback vs. static stall speed.
Incorrect torque converter
Install the correct torque converter. Refer to Torque Converter Replacement.
TRANSMISSION WILL NOT MAKE A SPECIFIC SHIFT
Condition
Action
Low engine power
Correct the engine condition.
Extreme fluid temperature
Inspect the cooling system and fluid level. Refer to Transmission Fluid
Checking Procedure .
Faulty speed sensor/circuit
Repair the circuit or replace the speed sensor or sensors. Refer to Speed
Sensor Replacement .
Faulty temperature sensor/circuit
Inspect for a temperature reading which inhibits shifts.
Faulty or misadjusted shift selector
Repair the shift selector.
TRANSMISSION WILL NOT STAY IN FORWARD OR
REVERSE
Condition
Action
Low fluid
Adjust the fluid level. Refer to Transmission Fluid Checking Procedure.
Leaking at solenoid assembly
Replace the solenoid assembly. Refer to Control Valve Solenoid
Replacement.
Low pressure
Repair the transmission.
Faulty solenoid - leaking
Replace the solenoid. Refer to Control Valve Solenoid Replacement.
