Raise the vehicle and support it securely on jackstands, then remove the transmission. If there's a leak, it's a good time to replace the front pump seal/O-ring for automatic transmissions. For manual transmission vehicles, remove the pressure plate and clutch disc, and check or replace the clutch components and pilot bearing. Look for factory paint marks indicating flywheel-to-crankshaft alignment; if absent, use a center-punch or paint to create alignment marks on both the flywheel/driveplate and crankshaft. Remove the bolts securing the flywheel/driveplate to the crankshaft, using a prybar or flywheel-holding tool as necessary to prevent the crankshaft from turning. Carefully remove the flywheel/driveplate, supporting it while removing the last bolt. Clean the flywheel with brake cleaner, inspecting for cracks, rivet grooves, burned areas, and score marks, and check for damaged ring gear teeth. Lay the flywheel on a flat surface to check for warpage with a straightedge. Clean and inspect the mating surfaces of the flywheel/driveplate and crankshaft, replacing the crankshaft rear seal if it's leaking. Position the flywheel/driveplate against the crankshaft, aligning the marks made during removal, and apply Teflon thread sealant to the bolt threads before installation. Use a flywheel-holding tool or a screwdriver to keep the flywheel/driveplate from turning while tightening the bolts to the specified torque. Complete the installation by reversing the removal procedure.