WORKHORSE CUSTOM CHASSIS
Service Manual
2007 W Series
SECTION
7.2
PAGE
482
Automatic Transmission – Allison
2007 W Series Chassis
© 2006 Workhorse Custom Chassis — All Rights Reserved
WSM082106
TRANSMISSION DOES NOT SHIFT PROPERLY
Condition
Action
Engine idle speed too fast during NEUTRAL to range shift
Adjust to correct idle speed.
Faulty throttle sensor/circuit
Repair or replace the sensor or circuit.
Faulty or sticking bleed ball in 1-2-3-4 clutch piston housing
Repair the transmission.
Excessive clutch running clearance
Rebuild the transmission and adjust clearances.
Shift adaptives not converged
Refer to FastLearn Procedure.
Instrument panel tachometer incorrect
Repair or replace the tachometer.
Incorrectly calibrated electronic speedometer
Calibrate the electronic speedometer.
Faulty speed sensor/circuit
Repair the circuit or replace the speed sensor. Refer to the speed sensor
DTCs.
Loose speed sensor
Tighten the speed sensor retaining bracket bolt. Refer to Speed Sensor
Replacement.
Degraded fluid
Change the transmission fluid and filter. Refer to Automatic Transmission
Fluid/Filter Replacement.
Incorrect fluid level
Correct the fluid level. Refer to Transmission Fluid Checking Procedure.
Low main pressure
Repair the transmission.
Intermittent conditions
Inspect the wiring harnesses and connectors.
Loose or damaged speed gear
Tighten the output flange bolt or replace the speed gear.
Sticking valves in the control valve body
Overhaul the control valve body assembly.
Leaking pressure control solenoids
Repair or replace the pressure control solenoids.
ABNORMAL ACTIVITIES OR RESPONSES
Condition
Action
Excessive Creep in First and Reverse Gears
Engine idle speed too high
Adjust to the correct idle speed.
Vehicle Moves Forward in Neutral
1-2-3-4 clutch failed or not released
Rebuild the 1-2-3-4 clutch
Vehicle Moves Backward in Neutral
3rd, 5th and reverse clutch failed or not released
Rebuild the 3rd, 5th and reverse clutch assembly.