NOTICE
A leaking air filter or air lines can cause slow or
hard shifting of the transmission, and eventual
transmission damage.
7.
Start the engine, and build pressure in the air
system. Check for air leaks at the filter housing
and air line connections; repair any leaks.
26–04 Allison Transmission
Fluid and Filter Change
When draining transmission fluid, check for evidence
of dirt or water contamination. A small amount of
condensation will appear in the fluid during operation.
Water contamination is normally characterized as a
milky discoloration of the transmission fluid. Obvious
contamination of the transmission fluid indicates a
leak between the water and fluid areas of the trans-
mission cooler. Inspect and pressure-test the cooler
to confirm the leak; replace leaking transmission
coolers.
1.
If the transmission fluid is not at normal operat-
ing temperature, run the engine until the fluid
reaches operating temperature: 160 to 200°F (71
to 93°C).
2.
Park the vehicle on a level surface, apply the
parking brakes, and chock the tires.
3.
Clean the area around the drain plug and the
transmission fluid pan. Place a drain pan under
the transmission and remove the drain plug. Ex-
amine the fluid as it drains.
4.
Remove the 12 mounting bolts (six each) from
the two filter covers.
NOTE: A considerable amount of fluid will drain
when the filter covers are removed.
5.
Remove the filter covers, O-rings, and two
square-cut seals from the transmission. See
6.
Remove the filters from the bottom of the control
module.
7.
Lubricate the new O-rings with transmission fluid,
then install them on the cover assemblies.
8.
Install a new square-cut seal on each cover as-
sembly, then install the fluid filter elements on
the cover assemblies.
9.
Install the filter and cover assemblies into the
filter compartment.
1
1
f260317b
09/15/2009
7
1
1
2
2
3
3
4
4
5
5
6
6
1.
Filter Cover
2.
Filter Element
3.
Filter Element O-Ring
4.
Square-Cut Seal
5.
Gasket
6.
Capscrew
7.
Drain Plug
Fig. 5, Allison Transmission Filter Location and
Components
Transmission
26
122SD and Coronado 132 Maintenance Manual, February 2016
26/5
