a1racer

this is a good one and there is one on the go jeep page that is very good as well

XJ Stryker

I am getting ready to do this job again so I guess it is time for a write up!

a1racer

make sure you take detailed pics as this can be a confusing job to do for the beginner shade tree mechanic. it took me about 6 hours to do

98 JeepJeep

and also get some good pics of the edges of the lower main cap/seal that need RTV put on them.....

a1racer

yeah this was a little confusing until i had it a part then i saw where to put it on at.

TrekkerJmm

here is a write up on changing the rear main seal, hope it helps...Tj
http://go.jeep-xj.info/HowtoRearMain.htm

98 JeepJeep

thats a good write up that shows where the RTV needs to be.

Cherokeesport2030

thanks for the help

fishtaconc

I had a similar problem with my '91 in '02, I took it to a mechanic come to find out was valve cover gasket leaking not rear main.

crashmurray1989cherokee

hey guys i have a bad rear main seal, and i dont have a lift on it yet. Should i pull the engine or just move the trany back to fix it? Its a tight fit to get the oil pan out with out a lift. Its a 1989 cherokee 4.0L automatic trany.

muddeprived

No, just raise the front end with a jack. jack it up a good 6-8" and you'll have enough room. Or if you have to, remove the axle. It's easier to remove the axle than it is to remove the engine or disconnect the tranny.

crashmurray1989cherokee

thanks it worked great every thing went well

streve

We are replacing rods n mains in a 97 HO 4.0, no need to pull the motor up to clear?? just disassemble all the control and suspension rods?

streve

the pan hits the front banjo housing. Also..it's a 4WD.

5-90

A few notes from experience:

1) Whatever year your rig, use the 1996-up sump gasket. It's one-piece moulded rubber, and that saves you fighting with the thing!

2) DO NOT OVERTIGHTEN the oil pan sump screws! (The small screws are 1/4"-20x1/2", the large ones are 5/16"-18x3/4")

3) You don't have to remove the transmission - the 242ci had a two-piece rear main for the entire production run. The rear main not, however, a "rope seal" - it's rubber moulded over a metal core. You can start the upper half out by using a short brass rod against the end and tapping with a hammer (use brass or bronze so you don't scuff or scratch the crankshaft.)

4) Before you take the first screw out, pour a cupful of clean engine oil and drop the new rear main in there to soak. Leave it in there until you're ready to put it in. This makes it easier to install, and the seal will pick up more quickly.

5) I've never put RTV on the ends of the seal - it protrudes slightly from the cap and block at both ends, when properly installed. Leaving it soaked in oil for all that time makes the rubber more pliant, and the seal will then seal against itself. I don't like putting anything on main caps - makes it entirely too easy to screw up bearing clearances.

6) Use LocTite #242 on the oil sump screws. Torque the 1/4" screws to 7 pound-feet, and the 5/16" screws to 11 pound-feet. The rear main cap gets torqued to 80 pound-feet.

7) You'll have to remove the starter to get it out of the way. Disconnect the negative battery cable, and the starter will probably take a 9/16" for one screw and a 15m/m socket for the other (one is 3/8", the other is 10m/m. No, I don't know why, either...)

Is your rig lifted? I was able to do a rear main on a rig with a 3" lift with all four paws on the ground (I actually had to re-crank it, but I had room to work.) If not, it can get dicey...

A) Jack the front end up and support by the frame rails until the axle gets to full droop. You should be able to see a bit of daylight (I prefer an inch or so) under each of the front tyres with the vehicle suspended by the frame rails.
B) If you need more room, use a 13m/m socket and remove the four nuts that hold the transmission mount to the crossmember. Jack the drivetrain assembly up by the transfer case. This gets you 3/4" or so at the bellhousing.
C) If that's not enough, take the spare tyre jack and wedge it in between a front frame rail and the front axle housing. Force the jack away from the engine - that should pick up the last little bit of clearance you'll need (you should see what I've got out in the driveway right now!)