I went thru the hassle of replacing the rear main seal as per the jeepin article. ( http://jeepin.com/features/rearmain ) Start and drove it, after a little bit it started leaking again. Leak slows at idle but seems pretty fast while driving/right after. I pressure washed the engine transmission to see if I could follow the leak. All I can tell is that is that seems to be coming from inside the flex plate cover driping off the bottom of the bell housing and flying back to the exhaust while driving. Is there any thing else that could be leaking? Or maybe the seal surface for the rear main is bad? Is there something else at the back that could be leaking profusely? So frustrated with the thing right now..

 

If its not your rear main the the next most likely is the rocker cover. The rocker cover gasket on the 4.0 can deteriorate, the engines leans to the back and a leak at the rear will run down and look like possible rear main. Check your rocker cover bolts and if the gasket looks rough plan on a replacement.

 

Recently had this same problem, but I didn't replace the RMS. I started with the VC and then when that didn't work went the the oil filter adapter o-rings. That stopped my leak. Point of the story, like it was previously stated, start high because oil is victim to gravity like everything else and will end up under the engine and look like a RMS leak.

 

Cruiser54's


I'd be looking up ABOVE first, and VERIFYING the source of the oil leak YOURSELF.
Everybody, who doesn't own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking.
Many mechanics, friends, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?
A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon right off the bat.

Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.
First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill".

Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
Revised 9-15-2012


His thread with a lot of useful information.
https://www.cherokeeforum.com/f51/cr...x-tips-153657/

 

X2 on the adapter O rings. It blows right back and drips from the bell-housing. You almost gotta check before you leave the car wash, in a minute it will be all over.

If the front CCV vent it not free to vent, crankcase pressure will make it **** out the RM.

 

You beat me to it, Quick Draw!! Good morning.