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11. Submerge a new oil pan gasket in transmission
fluid for five minutes. Then place the gasket on
the pan; do not use any substance as a gasket
retainer.
IMPORTANT: Do not use gasket-sealing com-
pounds any place inside the transmission or
where they might get washed into the transmis-
sion. Also, nonsoluble vegetable-based cooking
compounds or fibrous greases must not be used
inside the transmission.
12. Install the oil pan and gasket.
12.1 Guide the pan and gasket carefully into
place. Guard against dirt or foreign mate-
rial entering the pan. Retain the pan with
four 5/16–18 washer-head screws, in-
stalled by hand into the corners of the
pan.
12.2 Install the remaining seventeen washer-
head screws by hand, carefully threading
each through the gasket and into the
transmission. Bottom all of the screws
before tightening any of them.
12.3 Evenly tighten all 21 of the screws 10 to
15 lbf·ft (14 to 20 N·m). Check the gasket
fit while the screws are being tightened.
IMPORTANT: The oil pan bolts must main-
tain a minimum torque of 60 lbf·in (680
N·cm) after the oil pan gasket has taken a
set.
13. Install the fill tube at the side of the pan. Tighten
the tube fitting 90 to 100 lbf·ft (122 to 136 N·m).
14. Install the drain plug and gasket, and tighten the
plug 15 to 20 lbf·ft (20 to 27 N·m).
15. Replace the external (auxiliary) fluid filter.
16. Clean the area around the fill tube and remove
the dipstick. Using a clean funnel in the fill tube,
add transmission fluid. See Table 3 for approved
transmission lubricants, and Table 4 for lubricant
capacities.
17. Check and adjust the fluid level using the proce-
dure under "Checking the Fluid Level."
MD Series
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.
CAUTION
To prevent dirt from entering the transmission,
use only clean containers and fillers for the trans-
mission fluid. Do not use fillers or containers that
have been used for water or antifreeze. Dirt, water,
or antifreeze could damage the transmission.
1. Park the vehicle on a level surface and apply the
parking brakes.
2. Operate the vehicle until the transmission
reaches normal operating temperature: 160 to
200°F (71 to 93°C).
3. Clean the area around the drain plug and the
transmission fluid pan. Place a drain pan under
f260133a
1
2
3
4
5
6
10/05/94
1. Fluid Intake Tube
2. Filter Spacer
3. Internal Fluid Filter
4. Washer-Head Screw
5. Governor Pressure
Tube
6. Governor Feed Tube
Fig. 3, Allison AT Series Transmission Filter
Transmission 26
Acterra Maintenance Manual, March 2005 26/5