Rear Main Seal Bad...., I Think!?

[JG71B]

I expected more of a mess after a couple years. Exhaust is really mess BEHIND the trans. It leaks oil, not trans fluid at all. I stay within an hour of the house because of the amount of oil I lose. Drips right from where trans and engine butt up in the center when parked but stops eventually. Seems to only do it when driving and gets blown all over the underneath I have more than great oil pressure and wonder if that has anything to do with it. It doesnt leak from the oil pressure sending unit, intake is sealed.....Blowing out the back corners of valve cover gaskets? Or is the seal obvious (never dealt with one)? I did wipe the bottom of the oil pan and center link off but there wasnt much oil on them. Thoughts? Ideas?

 

[AR67GTX]

To me (I’m no expert) your rear seal is fine but it’s possible the seal retainer is leaking, maybe at the side seals. If the rear seal itself is leaking I believe you will find oil slung all around in the bell housing from being spun off by the crank and flywheel flange. To me your inside of bell housing doesn’t look dirty and oily enough for a rear seal leak of that magnitude. Unless it really leaks a lot but hasn’t been doing it long enough to plaster down a bunch of dirt and grit. Or am I mis-reading your pictures?


If the seal retainer leaks it just gravity-seeps out and down until it hits the slip stream and then back along the outside of the bell housing, transmission and on to your exhaust. However, don’t rule out possibly having a leaking valve cover, leaking intake manifold leak at the rear China wall or an oil pan leak (or some combination). Just my guess.

 

[MarPar]

To me (I’m no expert) your rear seal is fine but it’s possible the seal retainer is leaking, maybe at the side seals. If the rear seal itself is leaking I believe you will find oil slung all around in the bell housing from being spun off by the crank and flywheel flange. To me your inside of bell housing doesn’t look dirty and oily enough for a rear seal leak of that magnitude. Unless it really leaks a lot but hasn’t been doing it long enough to plaster down a bunch of dirt and grit. Or am I mis-reading your pictures?


If the seal retainer leaks it just gravity-seeps out and down until it hits the slip stream and then back along the outside of the bell housing, transmission and on to your exhaust. However, don’t rule out possibly having a leaking valve cover, leaking intake manifold leak at the rear China wall or an oil pan leak (or some combination). Just my guess.

Add to that possible leak list the oil pressure sender.

 

[MWbirdLOVER70]

Add to that possible leak list the oil pressure sender.

Or I changed mine 3x once and last time believe it or not my valve cover breather was plugged ( thought I had clean one from because at the time there was was no resto ones available and had a newer Mopar high domed chrome one on with chrome valve covers and during resto of the car put all my stock parts and covers back on ) bought a great used one and bingo no more rear seal leaks. Think since the breather was plugged so bad it built up to much internal pressure and was blowing oil out my rubber rear main seal. It’s been clean since 91 knock on wood.

 

[rickseeman]

The only thing I'm certain about is that you're a better man than me if you tackle that job.

 

[PRND21]

Do you have a PCV valve and breather on your engine?

 

[oldkimmer]

To me it looks like the oil is leaking past the top ok f the windage tray. Tell tail sign is how clean that area is. Kim

 

[Geoff 2]

You could nip up the oil pan bolts...& get lucky. But my guess is the rear seal or seal holder. When the engine is running, blowby increases pressure in the crankcase & helps find ' bad' seals.