Fluid Filter - A/T: Service and Repair

Removal Procedure
The HYDRA-MATIC 4T80-E transmission has a filter under the side cover that requires service only during transmission overhaul. Scavenging screens are beneath the bottom pan, which you must replace when you change the transmission fluid.
1. Raise the vehicle and support. Refer to Vehicle Lifting.
2. Place a drain pan under the transmission bottom pan in order to catch the fluid.

Important: Removing the bottom pan on the HYDRA-MATIC 4T80-E only partially drains the transmission fluid. The remaining fluid is held in the in the side cover and the torque converter. Removing the drain plug in the case after removal of the bottom pan will drain fluid from the side cover. You do not need to drain the torque converter during most service procedures.





3. Loosen the bottom pan bolts. Drain any fluid in the pan.
4. Remove the drain plug in the transmission case.
5. Remove the bottom pan, the transmission case bolts, and the seal.





6. Remove the left and the right scavenger screens.

Important: The bottom pan seal is NOT reusable. Replace the pan seal with a new part after removing the pan for any service.

7. Inspect the following parts for the conditions cited:
^ The scavenger screen lip seals in the transmission case for nicks or cuts. If damaged, replace.
^ The bottom pan and the transmission case for dents or nicks in the sealing surfaces. If damaged, replace.
^ The bolts for damaged threads. If damaged, replace.
For proper sealing, the bottom pan and the case sealing surfaces must be clean and dry. In order to maintain proper bolt torque, the bolts and the tapped holes in the case must be clean and dry.

Installation Procedure





1. Install the drain plug in the transmission case.
2. Install new left and right scavenger screens.





3. Install the bottom pan and a new seal. Finger tighten the bolts.

Notice: Refer to Fastener Notice in Service Precautions.





4. Tighten each of the 16 bolts 3 time in the sequence shown.
4.1. Tighten the pan bolts to 3 Nm (27 inch lbs.).
4.2. Tighten the pan bolts to 6 Nm (53 inch lbs.).
4.3. Tighten the pan bolts to 12 Nm (106 inch lbs.).

5. Lower the vehicle.
6. Add DEXRON(R)-III transmission fluid as required. Refer to Specifications.
7. Reset the transmission adapts.
8. Reset the transmission oil life indicator.