GM 12654640 Pattern 6-Bolt Crankshaft Flexplate

Raise the vehicle and support it securely on jackstands, then remove the transmission. Mark the relationship between the driveplate and the crankshaft with a marking pen, 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. If there is a retaining ring between the bolts and the driveplate, note which side faces the driveplate when removing it. Remove the driveplate from the crankshaft, wearing gloves to protect your fingers from the sharp edges of the ring gear teeth. Clean the driveplate to remove grease and oil, inspect the surface for cracks, and check for cracked and broken ring gear teeth, laying the driveplate on a flat surface to check for warpage. Clean and inspect the mating surfaces of the driveplate and the crankshaft, replacing the rear main oil seal if it is leaking before reinstalling the driveplate. Position the driveplate against the crankshaft, aligning the marks made during removal, and ensure correct installation with any alignment dowel or staggered bolt holes. Before installing the bolts, apply thread-locking compound to the threads and place the retaining ring in position on the driveplate. Wedge a screwdriver through the ring gear teeth to keep the driveplate from turning as you tighten the bolts in a criss-cross pattern to the specified torque. If the front pump seal or O-ring in the transmission is leaking, replace it at this time. The remainder of the installation follows the reverse order of removal.