Engine: Rear Main seal OR sump

[brooker]

Hello all, what im trying to find out whether its My rear main seal leaking or just the sump leaking its a 62 V8 hawk auto trans there is no oil around or on the flex plate seems to just be running down the front of cover, has anyone found a way of eliminating witch area its coming from Many thanks in advance,

[HAWK64]

Whilst you have the engine sump dropped down I would bite the bullet & replace the rear main seal set at the same time. With a little patience you can carefully remove the upper seal. Unfortunately, some people remove the engine which is not necessary. Good luck.

[doofus]

When i perform this step in frame i loosen all main caps a few turns and allow crank to hang down a hair. i push out old seal with piece of brass welding rod.cleaning groove is tricky but once done with small bore brush on pull wire roll in new seal and off set part line. a small dab of sealer on end is insurance. dab some sealer, just a thin film, on main cap and install. torque all caps. be sure seal lip faces front, in toward oil . this is a good time to check all main bearings for wear. i have tried a small mirror to see if it's the RMS or pan leaking but usually this is inconclusive, and messy.anyway , Good Luck, Doofus

[WCP]

I'll bet it is your pan seals. If the flex plate and exposed crank is dry, then it is unlikely the main seal. What I have recently found is that the leaks are coming from the front and rear pan seals due to the compression pressure being relaxed some by the deformation of the pan sides where the fasteners compress the side gaskets. Borrow a tip from GM and make some reinforcement strips to fit into the channels along the pan sides. I did this before I realized that my '97 pickup had that feature. I used 1/2" x 1/8" steel strips that fit into the channel and run from the front corner reinforcement to rear corner reinforcement. I re-used the pan fasteners but added a bit of red lock-tite to each, as well as the corner fasteners. This made a huge difference in front and back seepage. The only problem is that you have to drop the pan to accurately establish the 5/16" holes along the steel strip and flatten the pan/hole deformation before installing. The result is even side gasket squeeze-out and a season long dry pan. This assumes that your rocker cover gaskets aren't leaking down the back of the engine.
There could be a significant market for the strips!