leaking rear main

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Apr 24, 2003 | 12:00 PM

99banshee

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Joined: Apr 2003

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leaking rear main

what type of rear seal do 390's use, and how hard is it to change? I know I have to remove the tranny, but that's easy enough. I'm tired of impersonating the Exxon Valdez.

Apr 25, 2003 | 01:12 PM

William

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Joined: Feb 2000

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From: Sun River St. George

leaking rear main

Firstly changing the RMS is a real PITA! So before you do anything be sure it is the RMS and not a valve cover or intake manifold gasket. Sometimes (rarely) the oil gallery plug will leak/seap. Now lets talk about replacing the RMS. Loosen the motor mounts and raise the engine a few inches, block it with wood between the motor mount and the frame. Remove the oil pan bolts and lower the pan. Reach in between the pan and block and remove the oil pump and sump. Let these fall into the pan, and slide the pan out. Remove the rear main bearing cap, remove the upper portion of the RMS, clean everything with acetone and a razor blade. Don't use emory on the seal surface of the crankshaft, just wipe it clean with acetone. Oil and install the upper half of the seal, (Be sure it is facing the right way), off setting it about an 1/8th of an inch, oil and put the lower half of the seal in the main cap. also offset. Set the cap on and finger start the bolts. Slide in the side seals and tighten the main cap to specifications. Bend the nails a bit so they point away from the seal and drive them home. Trim any excess. Reinstall everything in reverse order of disassembly. This job is such a PITA I never do it unless the engine is out and if not out I pay somebody with a lift to do it.