Tools Required

1. Remove the radiator. Refer to Radiator Replacement in Engine Cooling.
2. Remove the air conditioning (A/C) condenser. Refer to Condenser Replacement in Heating Ventilation and Air Conditioning.
3. Remove the valve lifter pushrod guide. Refer to Valve Lifter Replacement .
4. Remove the timing chain and camshaft sprocket. Refer to Timing Chain and Sprocket Replacement .
5. Remove the balance shaft drive gear.



6. Remove the balance shaft driven gear bolt.

6.1.	Use a wrench in order to secure the balance shaft.

Place the wrench onto the balance shaft near to the balance shaft front bearing.

6.2.	Remove the balance shaft bolt.

6.3.	Remove the wrench from the balance shaft.

7. Remove the balance shaft driven gear.



8. Remove the balance shaft retainer bolts and retainer.




Important: The balance shaft and the balance shaft front bearing are serviced only as a package. Do not remove the balance shaft front bearing from the balance shaft.

9. Use a soft-faced hammer in order to remove the balance shaft from the engine block.
10. Clean and inspect the balance shaft, if necessary. Refer to Balance Shaft Cleaning and Inspection in Engine Mechanical - 4.3L Unit Repair.

Important: The balance shaft drive and balance shaft driven gears are serviced as a set. The set includes the balance shaft driven gear bolt.

1. Apply clean engine oil to the balance shaft front bearing.
2. Using J 36996 and J 8092 , install the balance shaft.




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.

3. Install the balance shaft retainer and bolts.

Tighten
Tighten the balancer shaft retainer bolts to 12 N·m (106 lb in).




4. Install the balance shaft driven gear.
5. If reusing the fastener, apply threadlock GM U.S. P/N 12345382, Canada P/N 10953489, or equivalent to the threads of the balance shaft driven gear bolt.
6. Install the balance shaft driven gear bolt.

6.1.	Use a wrench to secure the balance shaft.

Place the wrench onto the balance shaft near to the balance shaft front bearing.

6.2.	Install the balance shaft driven gear bolt.

Tighten

1. Tighten the balance shaft driven gear bolt a first pass to 20 N·m (15 lb ft).
2. Tighten the balance shaft driven gear bolt a final pass using J 36660-A an additional 35 degrees.
7. Remove the wrench from the balance shaft.
8. Rotate the balance shaft by hand in order to ensure that there is clearance between the balance shaft and the valve lifter pushrod guide. If the balance shaft does not rotate freely, check to ensure that the retaining ring on the balance shaft front bearing is seated on the case.



9. Install the balance shaft drive gear. DO NOT install the camshaft sprocket bolts at this time.



10. Rotate the camshaft so that the timing mark on the balance shaft drive gear is in the 12 o'clock position.



11. Remove the balance shaft drive gear.



12. Rotate the balance shaft so that the timing mark on the balance shaft driven gear is in the 6 o'clock position.



13. Position the balance shaft drive gear onto the engine camshaft.
14. Look to ensure that the balance shaft drive gear and the balance shaft driven gear timing marks are aligned.
15. Install the timing chain and the camshaft sprocket. Refer to Timing Chain and Sprocket Replacement .
16. Install the valve lifter pushrod guide. Refer to Valve Lifter Replacement .
17. Install the A/C condenser. Refer to Condenser Replacement in Heating Ventilation and Air Conditioning.
18. Install the radiator. Refer to Radiator Replacement in Engine Cooling.