GM 30012976 Front Propeller Shaft Assembly(On Esn)

Raise the rear of the vehicle and support it securely on jackstands. Block the front wheels. The transmission should be in Neutral. Crawl under the vehicle and visually inspect the driveshaft. Look for dents and cracks in the tube. If any are found, the drive-shaft must be replaced. Check for oil leakage at the front and rear of the driveshaft. Leakage where the driveshaft enters the transmission indicates a defective rear transmission seal. Leakage where the driveshaft enters the differential indicates a defective pinion seal. While still under the vehicle, have an assistant turn the rear wheel so the driveshaft will rotate. As it does, check for binding, noise and excessive play in the U-joints. The universal joints can also be checked with the driveshaft motionless, by gripping both sides of the joint and attempting to twist it. Any movement at all in the joint is a sign of considerable wear. Lifting up on the shaft will also indicate movement in the universal joints. Check the driveshaft mounting bolts at both ends to make sure they're tight. The above driveshaft checks should be repeated on all driveshafts. In addition check for grease leakage around the sleeve yoke, indicating failure of the yoke seal. Check for leakage where the driveshafts connect to the transfer case. The driveshafts must be lubricated periodically as indicated in the maintenance schedule. Use the grease gun to insert grease into the fitting. The driveshafts are lubricated at the fitting and also at the boot. Also pull back the boot at the rear of the axle and insert grease.