Rear

[Hard frank]

I'm about to tackle the rear main seal and was wondering if there is a DIY write up,just kinda what stump's to watch out for beforre hand thanks in advance

[Pete M]

the longer you let the engine sit before tackling this, the less oil will drip on your face while you're trying to work.   I prefer at least a day.

 

scraping off the old pan gasket sucks.  I used a straight razor blade for the bulk of it, then an sos style pad for the rest. 

 

buy 2 seals so you have a backup on hand if anything goes wrong.  return if unused.

 

you need some separation between the body and front axle to get the pan out.  either a lift kit installed, or jack up the body.

 

you'll want a brass punch to push the upper half of the seal started.  then pliers to pull it down and out

 

I prefer to let the silicone stuff cure overnight before starting up the engine.

 

 

I imagine there are a few youtube vids covering it  

 

 

[AZJeff]

There are TONS if videos on YouTube covering the R&R of the RMS and pan gasket on the 4.0   Often the video shows the job being done on a YJ, TJ, or XJ, but they are the same as the MJ, except for how one goes about getting the oil pan out after it is detached from the engine.

 

My preferred method to getting the pan out is to jack the vehicle up so the front wheels clear the ground, and then place jack stands under the "frame" by the lower control arm pickup points.  Then place the jack under front axle, and remove the front wheels.  Then lower the front axle down as far as it will go.  If that is STILL not enough to get the pan out, then remove the lower shock mounting bolts, and lower the axle a bit more with the jack.

 

Once the  pan is out, put some jack stands under the front axle to support it while you do the seal work.  Once you are ready to reinstall the pan, take the jack stands out and lower the front axle as needed to get the pan back in.

[Whitaker717]

This job is a nightmare. Lol. I tried it in my garage by myself. I actually got the old pan out and the new seal in but couldn’t get the new oil pan in. It’s the first time I ever had to throw in the towel on a project. I had to have it towed to the dealership for them to finish. I was pretty disappointed. AZ Jeff has the right idea. There is a good video on you tube of a guy jacking up the axle. Watch it and it will help. Have plenty of rags and don’t wear good clothes. It was a long project for me but I’m still kinda new to that stuff. If I had to do it again it would take me half the time probably. Good luck. 

[cruiser54]

Hey Frank, have you verified yourself that it's indeed the rear main seal leaking? Might wanna read this.

 

REAR MAIN SEAL DIAGNOSIS

OCTOBER 31, 2015 SALAD 3 COMMENTS

 

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: “Crap 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.  A little tip here. Rather than use a dizzy gasket, use an o ring instead. NAPA #727-2024. Tips 12 and 13 will help you get your distributor back in place correctly. 

 

 

 

[zomeizter]

OP, get you a Melling high volume oil pump and strainer and install them while you have the oil pan off...