Sierra 3500 Denali 2WD V8-6.0L (2011)
Wiring Harness: Service and Repair
Allison - Automatic Transmission
Wiring Harness Replacement
Special Tools
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J 44247 Internal Wiring Harness Installer
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J 44257 Main Wiring Harness Connector Remover
Removal Procedure
Warning: Refer to Battery Disconnect Warning (See: Starting and Charging/Battery/Service Precautions).
1. Remove the oil pan and transmission internal oil filter. Refer to Oil Pan Replacement (See: Fluid Pan/Service and Repair/Allison - Automatic
Transmission).
2. Disconnect the external wiring harness from the main transmission connector. Use J 44257 , if connector is not easily accessible.
Note: The main transmission connector is actually one end of the internal wiring harness that protrudes through the transmission case.
3. Place a 30 mm or 1 3/16 inch 12-point deep socket or box-end wrench (2) over the main transmission connector (1).
4. Push inward on the socket or wrench to release the retaining feet that attach the connector (1) to the transmission case.
5. Remove the wrench. Push inward on the electrical connector to separate from the transmission case.
6. Disconnect the internal wiring harness connectors (1) from the solenoids, the internal mode switch (IMS), and from the transmission fluid pressure
(TFP) switch.
Note: The solenoid retainers for shift solenoid 3 (SS3) and shift solenoid 2 (SS2) also retain tabs on the wiring harness U-channel. The solenoids
will remain in position even after the solenoid retainers are removed.
7. Remove the solenoid retainers (2) for SS3 and SS2.
8. Remove the internal wiring harness from the transmission.