rear main seal leak
Thread Starter
Junior Member
Joined: Feb 2010
Posts: 32
Likes: 0
From: West KY
Year: 1990
Model: Cherokee
Engine: 4.0 I6
I am gonna give a suggestion on doing a rear main. To get the top seal out and back in use a wooden dowel don't use metal. The reason I say this is if you slip and you score the wrong thing you could cause more issues then it's worth. Also take a dab of rtv at the ends to help seal it. Then make sure you torque that rear bearing cap to specs. If you over tighten it you will start leaking again. Also clean the crap out of that bottom end while you are down there. Also replace your oil pump as well and at the very least clean the pickup tube screen out. Reason I suggest the oil pump is you are down there the pump is old may as well put a good one in and it will also help improve oil pressure and flow. Just my 2 cents.
CF Veteran
Joined: Oct 2008
Posts: 2,543
Likes: 5
From: Stafford,VA
Year: 1998
Model: Cherokee
Engine: 4.0
I am gonna give a suggestion on doing a rear main. To get the top seal out and back in use a wooden dowel don't use metal. The reason I say this is if you slip and you score the wrong thing you could cause more issues then it's worth. Also take a dab of rtv at the ends to help seal it. Then make sure you torque that rear bearing cap to specs. If you over tighten it you will start leaking again. Also clean the crap out of that bottom end while you are down there. Also replace your oil pump as well and at the very least clean the pickup tube screen out. Reason I suggest the oil pump is you are down there the pump is old may as well put a good one in and it will also help improve oil pressure and flow. Just my 2 cents.
Thread Starter
Junior Member
Joined: Feb 2010
Posts: 32
Likes: 0
From: West KY
Year: 1990
Model: Cherokee
Engine: 4.0 I6
well, afternoon 3 on the rear main seal replacement. everything going good until i ran into the upper part of the main seal up in the block. Am I doing something wrong here? Just from reading the posts its like its a piece of cake to take this thing out but I'm having a hell of a time beating it on one end of the seal, all i'm doing is deforming . Has anybody else had problems with this? Suggestions?
Senior Member
Joined: Jan 2010
Posts: 999
Likes: 0
From: Brentwood, TN
Year: 2001
Model: Cherokee
Engine: 4.0
well, afternoon 3 on the rear main seal replacement. everything going good until i ran into the upper part of the main seal up in the block. Am I doing something wrong here? Just from reading the posts its like its a piece of cake to take this thing out but I'm having a hell of a time beating it on one end of the seal, all i'm doing is deforming . Has anybody else had problems with this? Suggestions?
Thread Starter
Junior Member
Joined: Feb 2010
Posts: 32
Likes: 0
From: West KY
Year: 1990
Model: Cherokee
Engine: 4.0 I6
sorry its been so long for a reply, but no, i wasn't able to get the top part of the seal out, so i replaced the bottom part, threw in some gasket sealer, and buttoned it all back up. Of course, it still leaks, almost wish i never did anything to it, and i've called around to area mechanics and they won't touch it. They say when they replace them two weeks later customers call back saying the seal is leaking again. They say it won't hurt anything, just gotta watch oil levels alot closer. So, my XJ marks its territory.
Junior Member
Joined: Sep 2009
Posts: 71
Likes: 0
From: Arizona
Year: 1990
Model: Cherokee
Engine: 4.0
sorry its been so long for a reply, but no, i wasn't able to get the top part of the seal out, so i replaced the bottom part, threw in some gasket sealer, and buttoned it all back up. Of course, it still leaks, almost wish i never did anything to it, and i've called around to area mechanics and they won't touch it. They say when they replace them two weeks later customers call back saying the seal is leaking again. They say it won't hurt anything, just gotta watch oil levels alot closer. So, my XJ marks its territory. 

Dyes RULE for finding leaks. Dump 2 bottles in the oil spout, run the engine for about 5 minutes, then use a black light to find the leaks. All your leaks will show a fluorescent greenish color. (The dye is fluorescent orange but when it mixes with the oil it turns greenish). I found four leaks yesterday. My leaks are: rear of oil pan, oil filter adapter, rear of valve cover, and oil sending unit (all famous 4.0L leaks).
The dye doesn't impact the utility of any fluid. Can be used in oil, tranny fluid, power steering, etc.
You can get the dye and black light on Amazon.
The dye doesn't impact the utility of any fluid. Can be used in oil, tranny fluid, power steering, etc.
You can get the dye and black light on Amazon.
Newbie
Joined: Sep 2013
Posts: 2
Likes: 0
From: Kauai in Hawaii west side
Year: 91 2dr
Model: Cherokee
Engine: 4.0l next sbc 402 not ls2
they told you worng i got a busted should i cant work over head or lift over 30lbs,and guess what i didnt with out droping the trany. all you do is drop the oil pan and take the rear bearing out and the bottom haft of the seal it right there the top haft, just take a small flat screw driver and tap it top haft there get something to grab that end with and pull or do like i did get it started then trun the crank over, and do the same thing puttin the new one in, and there you go. i got a 3 in lift and the front never left the ground so you know if i can do then you can do it.
Newbie
Joined: Sep 2013
Posts: 10
Likes: 0
From: Northern VA
Year: 1996
Model: Cherokee
Engine: 4.0 HO
Replaced my rear main on my cherokee couple months ago, had 176k on the odo when I replaced it. Sounds like you got the jist of everything based on everyone's responses here but here are my 2 cents
1. it may seem counterintuitive, but dropping the axle down, then jacking it back up a few inches actually provides more clearance than if it was all the way down, the axle moves forward when it rises... i was able to get my oil pan out without lifting the motor or trans this way (getting it back in... that's another story)
2. there should be a metal rod inside the gasket that you can see from the bottom, this is where you should be hitting the gasket to push it out other side. You probably are already seeing this
1. it may seem counterintuitive, but dropping the axle down, then jacking it back up a few inches actually provides more clearance than if it was all the way down, the axle moves forward when it rises... i was able to get my oil pan out without lifting the motor or trans this way (getting it back in... that's another story)
2. there should be a metal rod inside the gasket that you can see from the bottom, this is where you should be hitting the gasket to push it out other side. You probably are already seeing this
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Small Block Chevy. He feels if you get a rear main seal leak in a 4.0 Jeep, you should yank it out and put an SBC in.....
Newbie
Joined: Sep 2013
Posts: 2
Likes: 0
From: Kauai in Hawaii west side
Year: 91 2dr
Model: Cherokee
Engine: 4.0l next sbc 402 not ls2
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Don't you think when someone gotta ask they must be very young clicked on your:https://www.cherokeeforum.com/f51/cruiser54s-mostly-renix-tips-153657/ how long did it take you to gather that information I am impressed. Where I not switching to a SBC (the 406 kind) I would copy / paste keeping them for reference I will still copy and paste if can?
Since 1984 through 1992 when I was Service Manager and Shop Foreman at a Jeep dealer. We had direct access to JeepTech and got some good, most times unpublished, technical tips from them.
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