GM 12555640 Engine Flywheel

Raise the vehicle and support it securely on jack stands, then remove the transmission. Mark the relationship between the driveplate and the crankshaft with a marker or similar device, then remove the bolts that secure the driveplate to the crankshaft. If the crankshaft turns, wedge a screwdriver in the ring gear teeth to jam the driveplate. Remove the driveplate from the crankshaft. Since the driveplate is fairly heavy, be sure to support it while removing the last bolt. Clean the driveplate to remove grease and oil. Inspect the surface for cracks, and check for cracked and broken ring gear teeth. Lay the driveplate on a flat surface to check for warpage. Clean and inspect the mating surfaces of the driveplate and the crankshaft. If the rear main oil seal is leaking, replace it before reinstalling the driveplate. Position the driveplate against the crankshaft. Be sure to align the marks made during removal. Note that some engines have an alignment dowel or staggered bolt holes to ensure correct installation. Before installing the bolts, apply thread locking compound to the threads and place the retaining ring (if equipped) in position on the driveplate. Wedge a screwdriver through the ring gear teeth to keep the driveplate from turning as you tighten the bolts to the torque specifications. If the transmission front pump seal/o-ring is leaking, now would be a very good time to replace it. The remainder of installation is the reverse of removal.