Important: Do not raise the engine block by the crankshaft balancer to perform this service procedure. Damage to the crankshaft balancer or the crankshaft may occur.

Caution: Before servicing any electrical component, the ignition and start switch must be in the OFF or LOCK position and all electrical loads must be OFF, unless instructed otherwise in these procedures. If a tool or equipment could easily come in contact with a live exposed electrical terminal, also disconnect the negative battery cable. Failure to follow these precautions may cause personal injury and/or damage to the vehicle or its components.

1. Disconnect the battery negative cable from the battery. Refer to Battery Cable Replacement .



2. Remove the oil level indicator and tube from the engine. Refer to Oil Level Indicator and Tube Replacement .
3. Raise the vehicle and support with safety stands. Refer to Lifting and Jacking the Vehicle in General Information.
4. Drain the engine oil into a suitable container.
5. Remove the flywheel inspection cover, if equipped.
6. Remove the transmission from the vehicle with coil spring suspension only.

•	For the 4L80E, refer to Transmission Replacement

•	For the NV4500, refer to Transmission Replacement




7. Remove the flywheel from the crankshaft. Refer to Engine Flywheel Replacement .
8. Remove the transmission oil cooler line retaining clip nuts.
9. Remove the transmission oil cooler line retaining clip.



10. Remove the oil pan bolts from the oil pan.
11. Remove the oil pan from the engine block.



12. Remove the rear seal on the from the oil pan.
13. Clean the old RTV sealant from the oil pan and engine block.
14. Clean all the oil and grease from the sealing surfaces. Refer to Engine Block Clean and Inspect .

1. Apply a 2 mm (1/16 in) bead of RTV sealant GM P/N 12345739 to the oil pan rear seal at the inside corners where the seal meets the rear crankshaft bearing cap on the engine block.



2. Install the oil pan rear seal to the rear crankshaft bearing cap before the sealer starts to dry.
3. Apply a 5mm (3/16 in) bead of RTV sealant GM P/N 12345739 to the oil pan sealing surface, inboard of the bolt holes. Install the oil pan before the sealer starts to dry.



4. Install the oil pan to the engine block.




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.

5. Install the oil pan bolts to the engine block.

Tighten

1. Tighten all except the two rear bolts bolts to 10 N·m (89 lb in).
2. Tighten the rear two bolts to 23 N·m (17 lb ft).
6. Install the transmission oil cooler line retaining clip nuts.
7. Install the transmission oil cooler line retaining clip.



8. Install the flywheel to the crankshaft. Refer to Engine Flywheel Replacement .
9. Install the transmission if the vehicle is equipped a coil spring suspension.

•	For the 4L80E, refer to Transmission Replacement

•	For the NV4500, refer to Transmission Replacement

10. Install the flywheel inspection cover if removed.
11. Remove the safety stands and lower the vehicle.



12. Install the oil level indictor and tube to the engine block. Refer to Oil Level Indicator and Tube Replacement .
13. Fill the crankcase with engine oil. Refer to the owner's manual for the appropriate grade and capacity.
14. Connect the battery negative cable to the battery. Refer to Battery Cable Replacement .