WORKHORSE CUSTOM CHASSIS
Service Manual
2007 W Series
SECTION
7.2
PAGE
466
Automatic Transmission – Allison
2007 W Series Chassis
© 2006 Workhorse Custom Chassis — All Rights Reserved
WSM082106
• J 28431-6 Fluorescent Oil Dye - 6 1 oz
• J 42220 Universal 12V Leak Detection Lamp Dye and
Black Light Method
Use the J 42220 and the J 28431-6 to isolate the leak
point. Fluid dye and black light kits are also available
from various tool manufacturers. All transmissions that
are diagnosed, that require replacement due to leakage,
must be diagnosed with the leak dye and black light
method.
1. Follow the manufacturer’s instructions in order to
determine the amount of dye to use.
2. Detect the leak with the black light.
3. Make the necessary repairs.
GENERAL METHOD
1. Verify that the leak is transmission fl uid.
2. Thoroughly clean the suspected leak area.
3. Operate the vehicle for 24 km (15 mi), or until normal
operating temperatures are reached.
4. Park the vehicle over clean paper or cardboard.
5. Shut OFF the engine.
6. Look for fl uid spots on the paper.
7. Make the necessary repairs.
POWDER METHOD
1. Thoroughly clean the suspected leak area with
solvent.
2. Apply an aerosol type powder, such as foot powder, to
the suspected leak area.
3. Operate the vehicle for 24 km (15 mi), or until normal
operating temperatures are reached.
4. Shut OFF the engine.
5. Inspect the suspected leak area.
6. Trace the leak path through the powder in order to fi nd
the source of the leak.
7. Make the necessary repairs.
FIND THE CAUSE OF THE LEAK
Pinpoint the leak and trace the leak back to the source.
You must determine the cause of the leak in order to
repair the leak properly. For example, if you replace a
gasket, but the sealing fl ange is bent, the new gasket
will not repair the leak. You must also repair the bent
fl ange. Before you attempt to repair a leak, check for the
following conditions, and make repairs as necessary:
• Gaskets Fluid level/pressure is too high
• Plugged vent or drain-back holes
• Improperly tightened fasteners
• Dirty or damaged threads
• Warped fl anges or sealing surface
• Scratches, burrs, or other damage to the sealing
surface
• Damaged or worn gasket
• Cracking or porosity of the component
• Improper sealant used, where applicable
• Incorrect gasket
• Seals Fluid level/pressure is too high
• Plugged vent or drain-back holes
• Damaged seal bore
