4L80-E/4L85-E Automatic Transmission
Transmission Replacement
Tools Required
- J 21366 Converter Holding Strap
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the rear propeller shaft.
3. Support the transmission with a suitable jack.
4. Remove the transmission mount nuts.
5. Remove the transmission support bolts/nuts.
6. Remove the transmission support.
7. Raise the transmission slightly and remove the transmission support from the vehicle.
8. Remove the exhaust manifold pipe.
9. Remove the transfer case, if equipped. Refer to: Service and Repair
10. Remove the transmission mount bolts and mount.
11. Ensure the transmission manual shaft is positioned in mechanical park.
12. Remove the retainer that secures the cable to the bracket.
13. Remove the range selector cable end (2) from the transmission range selector lever ball stud (1).
14. Depress the tangs and remove the cable from the bracket.
15. Disconnect the following electrical connectors:
- Input speed sensor (1)
- Output speed sensor (3)
- Park/neutral position (PNP) switch (5)
- Transmission (4)
16. Disconnect the oxygen sensor (HO2S) electrical connector.
17. Disconnect the wire harness clip (2) from the bracket on the left side of the transmission.
18. Cut the tie strap to separate the vent hose from the wiring harness.
19. Remove the flywheel inspection cover.
20. Mark the torque converter to flywheel orientation.
21. Remove the torque converter bolts.
22. If equipped with a 6.0L engine, remove the exhaust hanger mounting bracket bolts and bracket.
23. If equipped with a 6.0L or 8.1L engine, remove the exhaust hanger mounting bracket bolts and bracket.
24. Disconnect the transmission oil cooler lines.
25. Plug the transmission oil cooler line fittings.
26. Remove the stud on the left side of the transmission.
27. Remove the remaining transmission studs.
28. Install the J 21366 onto the transmission bell housing to retain the torque converter.
29. Pull the transmission straight back.
30. Remove the transmission from the vehicle.
31. Flush the transmission oil cooler and lines at this time.
Installation
1. Install the transmission to the vehicle.
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: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
4. Install the transmission studs.
Tighten
Tighten the studs to 50 Nm (37 lb ft).
5. Install the stud on the left side of the transmission.
Tighten
Tighten the stud to 50 Nm (37 lb ft).
6. Remove the plugs from the transmission oil cooler line fittings.
7. Connect the transmission oil cooler lines.
8. If equipped with a 6.0L or 8.1L engine, install the exhaust hanger mounting bracket and bolts.
Tighten
Tighten the bolts to 12 Nm (106 lb in).
9. If equipped with a 6.0L engine, install the exhaust hanger mounting bracket and bolts.
Tighten
Tighten the bolts to 12 Nm (106 lb in).
10. Align the torque converter to the flywheel.
11. 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.
12. 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.
13. Install the torque converter bolts.
Tighten
Tighten the bolts to 60 Nm (44 lb ft).
14. Install the flywheel inspection cover.
Tighten
Tighten the bolts to 33 Nm (24 lb ft).
15. Connect the following electrical connectors:
- Input speed sensor (1)
- Output speed sensor (3)
- PNP switch (5)
- Transmission (4)
16. Connect the HO2S electrical connector.
17. Connect the wire harness clip (2) to the bracket on the left side of the transmission.
18. Depress the tangs and install the cable to the bracket.
19. Install the range selector cable end (2) to the transmission range selector lever ball stud (1).
20. Ensure the transmission manual shaft is positioned in mechanical park.
21. Install the retainer that secures the cable to the bracket.
22. Install the transmission mount and bolts.
Tighten
Tighten the bolts to 25 Nm (18 lb ft).
23. Install the transfer case, if equipped. Refer to: Service and Repair
- Transfer Case Assembly Replacement in Transfer Case - NVG 246-NP8
- Transfer Case Assembly Replacement in Transfer Case - BW 4482-NR4
24. Install the exhaust manifold pipe. Refer to Exhaust Manifold Pipe Replacement in Engine Exhaust.
25. Install the transmission support.
26. Install the transmission support bolts/nuts.
Tighten
Tighten the bolts to 95 Nm (75 lb ft).
27. Install the transmission mount nuts.
Tighten
Tighten the nut to 50 Nm (37 lb ft).
28. Remove the support from the transmission.
29. Install the rear propeller shaft.
30. Fill the transmission fluid.
31. Connect the negative battery cable.
32. Fill the transmission to the proper level with DEXRON� VI transmission fluid.
Important: It is recommended that transmission adaptive pressure (TAP) information be reset.
Resetting the TAP values using a scan tool will erase all learned values in all cells. As a result, The ECM, PCM or TCM will need to relearn TAP values. Transmission performance may be affected as new TAP values are learned.
33. Reset the TAP values.