4L80-E/4L85-E Automatic Transmission

Transmission Replacement
^ Tools Required
- J 21366 Converter Holding Strap

Removal Procedure





1. Raise the vehicle. Refer to Vehicle Lifting.
2. Drain the transmission fluid.
3. Remove the rear propeller shaft.
4. Support the transmission with a suitable jack.
5. Remove the transmission support. Refer to Transmission Support Replacement in Frame and Underbody.
6. Remove the exhaust manifold pipe.
7. Remove the transmission mount.
8. Remove the transfer case, if equipped.





9. Remove the range selector cable from the transmission range selector lever ball stud and bracket. .
10. Disconnect the electrical harness from the park/neutral position switch, the input speed sensor, and the output speed sensor.
11. Disconnect the wire harness from the wire loom on the left side of the transmission.
12. Cut the tie strap to separate the vent hose from the wiring harness.





13. Remove the flywheel inspection cover.
14. Mark the torque converter to flywheel orientation.
15. Remove the torque converter bolts.





16. Remove the transmission heat shield.





17. Disconnect the transmission oil cooler lines from the transmission. Refer to Transmission Fluid Cooler Line Quick Connect Fitting.
18. Plug the transmission oil cooler line connectors in the transmission case.





19. Remove the stud and the bolt on the right side securing the transmission to the engine.





20. Remove the remaining six studs and the one bolt securing the transmission to the engine.
21. Install the J 21366 onto the transmission bell housing to retain the torque converter.
22. Pull the transmission straight back.
23. Remove the transmission from the vehicle.
24. Flush the transmission oil cooler and lines at this time.

Installation Procedure





1. Install the J 21366 onto the transmission bell housing to retain the torque converter.
2. Raise the transmission into place and remove the J 21366 from the transmission.
3. Slide the transmission straight onto the locating pins while lining up the marks on the flywheel and the torque converter. The torque converter must rotate freely by hand.

Notice: Refer to Fastener Notice in Service Precautions.

4. Install studs and bolt securing the transmission to the engine.
^ Tighten the studs and the bolt to 50 Nm (37 lb ft).





5. Install the stud and bolt on the right side securing the transmission to the engine.
^ Tighten the stud and the bolt to 50 Nm (37 lb ft).





6. If reusing the torque converter bolts with a 6.0L engine, clean the bolt threads and apply Loctite 242 GM P/N 12345382 (Canadian P/N 10953489), or equivalent to the threads prior to installation.
7. If reusing the torque converter bolts with a 8.1L engine, clean the bolt threads and apply Loctite 272 GM P/N 12345493 (Canadian P/N 10953488), or equivalent to the threads prior to installation.
8. Line up the marks made during removal and install the flywheel to torque converter bolts.
^ Tighten the bolts to 60 Nm (44 lb ft).
9. Install the torque converter cover to the transmission.
10. Install the bolts securing the torque converter cover.
^ Tighten the bolts to 33 Nm (24 lb ft).





11. Install the vent hose to the wiring harness using a new tie strap.
12. Connect the wiring harness to the wiring loom on the left side of the transmission.
13. Connect the electrical harness to the park/neutral position switch, the input speed sensor, and the output speed sensor.
14. Install the range selector cable to the transmission range selector lever ball stud and bracket.





15. Install the transfer case, if equipped.
16. Install the transmission mount.
17. Install the exhaust manifold pipe.
18. Install the transmission support. Refer to Transmission Support Replacement in Frame and Underbody.
19. Remove the transmission jack.
20. Install the rear propeller shaft.





21. Connect the transmission oil cooler lines to the transmission. Refer to Transmission Fluid Cooler Line Quick Connect Fitting.





22. Install the transmission heat shield.
23. Install the bolts securing the heat shield to the transmission.
^ Tighten the bolts to 17 Nm (13 lb ft).
24. Lower the vehicle.
25. Fill the transmission to the proper level with Dexron(R) III transmission fluid.