Rear Main Seal Replacement

[bllprk]

Purchased my 2018 with 40,000 miles. Noticed oil dripping between the bell housing and engine.

Eventually replaced the seal while replacing the clutch. Dry as a bone until I added a flush to the oil trying to resolve a rough idle issue (VVL or VVT). The seal blew during the 20 min I ran the engine for the flush.

The seal leaked bad. Oil puddles in the bell housing and coating everything. A 6 inch diameter oil spot every morning…

For the first part of the job refer to the numerous posts about installing a clutch.

The reason for this post is some tips:

You must remove the upper oil pan to replace the seal. Once the transmission is off, remove the 19 fasteners plus the two on the seal itself. There is a pry location on the passenger side. You must clean off the old RTV.

Install the seal first. RTV is required around the bottom two holes.

Take the time to center the seal before you tighten the rear main seal bolts. If you don’t pay attention, it will tighten with it off center.

Then apply your RTV and fasten the upper oil pan per the RTV instructions.

Make sure you clean the crank shaft surface.

I couldn’t find much info on the topic and wanted to add this.

Note: I had assumed I could replace it without removing the oil pan. There is no way to properly make the RTV gasket as well as the seal was not concentric at all with the crank shaft.

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[toothirtyj]

Thanks for the post. Did you happen to notice where specifically, around the seal, it was leaking?

 

[bllprk]

I believe it came thru the seal itself. If you zoom in you can see a nice drip. Lots of oil around the starter as well. Also puddles of oil in the bell housing.

That said, I didn’t feel or see any damage on the seal.

I think the oil was flung to the sides of the bell housing…

 

[bllprk]

One more picture.

 

[PotterJLUR]

99.9% of the time owners think they have and rear main seal leak it is the oil cooler running down the back of the motor.

 

[bllprk]

99.9% of the time owners think they have and rear main seal leak it is the oil cooler running down the back of the motor.

So I guess I was the 0.1% .... Twice!

 

[mwilk012]

So I guess I was the 0.1% .... Twice!

At some point you might want to reevaluate what you are doing to your Jeeps.

 

[Gregj]

You didn’t happen to make any trips through swamp’s did you?

Gregj

 

[mwilk012]

You didn’t happen to make any trips through swamp’s did you?

Gregj

Lol, exactly my point.

 

[bllprk]

Yeah, I should keep to the mall...

 

[Gregj]

Ok, we do similar things with our Jeeps, minus the swamps.

Greg

 

[mwilk012]

Yeah, I should keep to the mall...

Nothing wrong with that, but its like saying radiator leaks are common if you keep jamming sticks through it. You're just thrashing that seal and experiencing failures that aren't at all common.

 

[azjl#3]

are you sure it says rtv, or is it FIPG, big difference.

 

[Spank]

99.9% of the time owners think they have and rear main seal leak it is the oil cooler running down the back of the motor.

I've had the pleasure of having to replace both.

 

[bllprk]

Nothing wrong with that, but its like saying radiator leaks are common if you keep jamming sticks through it. You're just thrashing that seal and experiencing failures that aren't at all common.

I took full responsibility for the second leak. Happened the minute I added extra fluid to perform an engine flush.

I do believe 99.9% is an exaggeration on oil cooler. In fact I replaced mine based on those posts. It wasn’t actually bad at 78k.

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