WORKHORSE CUSTOM CHASSIS
Service Manual
Automatic Transmission – Allison
2007 W Series
© 2006 Workhorse Custom Chassis — All Rights Reserved
SECTION
7.2
PAGE
447
2007 W Series Chassis
WSM082106
Examine the drained fl uid for evidence of water.
Obvious water contamination of the transmission fl uid
or transmission fl uid in the cooling water from the heat
exchanger indicates a leak between the water and fl uid
areas of the cooler. Inspect and pressure test the cooler
to confi rm the leak. Replace leaking coolers.
NOTICE:
Engine coolant in the transmission hydraulic system
Engine coolant in the transmission hydraulic system
requires immediate action. Failure to clean or replace
requires immediate action. Failure to clean or replace
all contaminated components may result in premature
all contaminated components may result in premature
transmission failure.
transmission failure.
1. Examine the drained fl uid for evidence of engine
coolant.
2. Examine the drained fl uid for evidence of metal.
Metal particles in the fl uid, other than minute particles
normally trapped in the oil fi lter, indicate internal
transmission damage. When this occurs, inspect the
inside of the oil pan for excessive metal particles.
Refer to Oil Pan Replacement .
3. Metal contamination requires complete transmission
disassembly.
NOTICE:
Flush the transmission cooling system and inspect for
Flush the transmission cooling system and inspect for
restrictions following a transmission failure. Failure to
restrictions following a transmission failure. Failure to
repair or replace restricted oil cooling system compo-
repair or replace restricted oil cooling system compo-
nents may result in premature transmission failure.
nents may result in premature transmission failure.
4. Clean all internal and external hydraulic circuits,
cooler, and all other areas where the particles could
lodge. Refer to Automatic Transmission Oil Cooler
Flushing and Flow Test .
LINE PRESSURE CHECK
Checking main line pressure helps to determine if a
transmission malfunction is due to a mechanical or an
electrical condition. Properly making these pressure
checks requires transmission and vehicle, or test stand,
preparation, recording of data, and comparing recorded
data against specifi cations provided.