Sierra 3500 Denali 2WD V8-6.0L (2011)
1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle (See: Maintenance/Vehicle Lifting/Service and Repair).
2. Place a drain pan under the vehicle.
3. Remove the propeller shaft. Refer to One-Piece Propeller Shaft Replacement (See: Drive/Propeller Shafts, Bearings and Joints/Drive/Propeller
Shaft/Service and Repair/One-Piece Propeller Shaft Replacement) or Two-Piece Propeller Shaft Replacement (See: Drive/Propeller Shafts,
Bearings and Joints/Drive/Propeller Shaft/Service and Repair/Two-Piece Propeller Shaft Replacement).
4. Remove the case extension housing rear oil seal. Use a flat bladed tool and carefully pry the seal from the housing.
5. Inspect the case extension housing for damage. Replace the extension housing if necessary. Refer to Case Extension Assembly Replacement (See:
Extension Housing/Service and Repair/4L60-E/4L65-E/4L70-E - Automatic Transmission).
Installation Procedure
1. Lubricate the inside diameter of the new seal with J 36850 .
2. Use the J 21426 with a soft faced mallet to install the seal.
3. Install the seal to the extension housing.
4. Install the propeller shaft. Refer to One-Piece Propeller Shaft Replacement (See: Drive/Propeller Shafts, Bearings and Joints/Drive/Propeller
Shaft/Service and Repair/One-Piece Propeller Shaft Replacement) or Two-Piece Propeller Shaft Replacement (See: Drive/Propeller Shafts,
Bearings and Joints/Drive/Propeller Shaft/Service and Repair/Two-Piece Propeller Shaft Replacement).
5. Remove the drain pan and lower the vehicle.
6. Fill the transmission to the proper level with DEXRON(R) III transmission fluid. Refer to Transmission Fluid Level and Condition Check (See:
Testing and Inspection/Component Tests and General Diagnostics/4L60-E/4L65-E/4L70-E - Automatic Transmission/Transmission Fluid Level
and Condition Check).
