Rear Main Seal Questions

I have searched quite a bit to try and answer these questions but have been unable to. So I have a 2001 stock XJ 4.0 Auto (AW4). It started leaking oil quite heavily while driving up a mountain with a very full load of passengers. The oil dripped down onto exhaust pipe causing smoke which I noticed and pulled over. Didn't lose much oil so engine is fine that way but now I am trying to address the leak. I have already replaced valve cover gasket and oil filter adapter o-ring and have checked that there isn't any oil leaking near the oil pressure switch but still some oil appears on the inspection plate between the transmission and the oil pan. I am planning to replace the rear main seal and oil pan gasket but am having a lot of trouble getting the pan dropped. There is a small plastic piece that keeps me from being able to remove the last two bolts in the oil pan nearest the inspection plate.

What is this plastic piece? Will it come off if I remove the inspection plate? I can't get the plate off because the exhaust pipe keeps the 18mm corner bolt from being removed.

I've seen a lot of threads that say you have to remove the catalytic converters from the exhaust manifold and take off the exhaust (which would solve the bolt problem) to drop the pan but is that absolutely necessary? I basically just want to drop the oil pan as easily as possible to replace the rear main seal and oil pan gasket, but now it looks like i have to remove the intake manifold to access the exhaust manifold bolts to remove the catalytic converters to move the exhaust pipes to pull the bolt from the access panel to get that little plastic piece out of the way to get those last two bolts out of the oil pan. Complicated much? Haha I think I may be able to get the cats off without removing the intake manifold but it looks like a big PITA! Anyway I just want to know what is the bare minimum I can do to get the seal/gasket replaced. If the little plastic piece isn't real integral to the vehicle I can cut it to get access to the two bolts but I don't want to do that without knowing what the plastic piece is/does. I have seen pics online of earlier model cherokees without that piece but both this car and another 2000 xj have it.
Also- a guy on a different thread said he just put a heavier oil (10w40) and stop leak in and that solved the problem of a slow leak from around the inspection panel. I'm concerned with the longevity of this jeep (it's a daily driver not really for wheeling) so would this "solution" affect the overall life of the engine negatively at all?

Yeah you'll have to drop the exhaust, maybe have to drop the exhaust mount near the transfer case so it will drop down far enough. That plastic thing is like a cover do keep debris out. Thicker oil wont fix anything, but possibly slow it down, but its a band aid. The pan has to drop pretty far down to clear the pick up tube.

Ok thanks mtbxj87. In your opinion, is it easiest to take the time to remove the intake manifold to make it easier to detach the exhaust? I haven't removed the intake manifold before so I'm a little hesitant lest I get myself in over my head..
And will that plastic piece come off easily enough when I take off the inspection plate?
Thanks again!

You may be able to take those three bolts out at the down pipe which would allow you to swing the mini-cat Y-pipe out far enough. It should also allow you to slide the rear exhaust forward and back enough to get the bolt out, if the inspection cover isn't slotted for that bolt. One or two of the inspection plate bolts are slotted so you don't have to get the bolt out, just loose. Are you sure you can't force that plastic rubbery piece out of the way enough to get the socket on?

Unfortunately, the three bolts which hold the exhaust pipe together just below the "Y" are rusted so badly I'd have to cut them or the pipe to get it separated so I was hoping to avoid that.
You're right about the plate being slotted. I hadn't noticed that before. With the other bolts out I can now move the plate around (it still doesn't want to come right out but with a little force I can probably pull it out). With the plate loose though I can see up behind it but it doesn't look like there is any way to get that plastic piece out. I have tried to force the plastic piece aside to access the bolts but it's surprisingly rigid and I can't get a socket on the bolt head..
Thanks for your help! I'm thinking there isn't any way around removing the cats/exhaust but if there is it'd be great! Also I'm still not seeing a way to get that plastic piece out of the way even with the plate out..
Anyway thanks again! I'll take all the help I can get!

Ok quick update: by pounding a larger socket up towards the bolts I was able to convince the rubber piece to become flexible enough to allow the right sized socket access to the bolts (which are 1/2" whereas all the other bolts on the oil pan were 7/16").
So now my only question is: do I absolutely have to disconnect the exhaust to make enough room to slide the oil pan out? I keep reading conflicting statements (most ppl say yes, a few have said they did it without removing it).
Thanks!

I don't see how you are going to be able to do it without cutting and punching out the 3 bolts at the down pipe or removing the manifolds at head. You might even need to remove the starter. Folks who can do this the easiest have 3" or more lift. Keep in mind the oil pump pickup is in deep part of the pan and you need to clear that and the axle. Tie the tranny cooler lines towards the frame rail. Make sure your engine is lifted or your axle is drooping. If you go the axle droop method with no lift, you may need to disconnect the steering stabilizer, shocks, and track bar. Sometimes it is easier to disconnect more up front than spend a lot of time trying to make it work. Be sure to read the FSM and use the sealers and gasket makers/RTV where specified. Most people don't want to do this again because they cut the seal or have a leak.

I guess you won't know until you try. I dropped my front axle out of the way and had no trouble otherwise, but mine's older. I will suggest that if it comes to removing manifolds, get the freeze plugs while you're in there.

I dropped everything but the control arms.

I think I'm gonna try dropping the pan without removing exhaust. I already have the starter out and the jeep supported under the frame so the axle is hanging (but nothing is detached). When my coffee is all gone it'll be the moment of truth! Thanks for your help!

Well more troubles have ensued but I think once I get the track bar disconnected (drag link already disconnected from pitman) and disconnect my shocks to allow the axle to hang a bit lower I should be able to find success! We'll see!

If you are going that far, you might as well pop off the four control arm bolts and just roll the axle out.

I just did my rear main and oil pan gasket huge pain glad i had a lift to borrow but i had to remove my starter as for the trans dust plate i just stuck a pry bar up there so i could push it away from the pan to slip it out

2001XJRedBarron said:

Ok quick update: by pounding a larger socket up towards the bolts I was able to convince the rubber piece to become flexible enough to allow the right sized socket access to the bolts (which are 1/2" whereas all the other bolts on the oil pan were 7/16").
So now my only question is: do I absolutely have to disconnect the exhaust to make enough room to slide the oil pan out? I keep reading conflicting statements (most ppl say yes, a few have said they did it without removing it).
Thanks!

Click to expand...

I just used an 11 and 13mm for the pan and i think a 14 or bigger for the main seal

On the 4.0L, if it threads directly into the block or head its standard thread (not metric) though some sizes are close such as 7/16"-11mm and 1/2"-13mm. AMC/Chrysler did not rethread the engine to metric. A good example is the starter. The bolt that threads into the block is standard thread. The bolt that threads into the starter is metric.

Subscribed... I have an 01 XJ and think the Rear Main will need to be replaced soon. I don't have a lift on my rig so this data should be pertinent to my work as well.

I had to disconnect sway bars and shocks to get the axle to drop enough, not that much work but once the axle was far enough down it made it pretty easy. I didn't see the need to fight with finding a sweet spot to get the pan out Vs. a few bolts to get the sway bar and shocks free to gain a lot of clearance.

Ok final update: Job complete! I didn't have to remove the exhaust! What I did disconnect: shocks, track bar, drag link, starter and inspection plate. When supported under the frame with the axle hanging this provided ample space to remove the pan. Might not have to remove the starter but mine was bad anyway. Thanks for everyone's help!

Thanks for the update. Any issues during the install process? All leaks gone now?