Remove the exhaust, you’ll be cursing the entire time if u don’t and end up removing it anyway
Rear Main Seal Replacement (4.0)
- Thread starter Chris
- Start date
Non-Rubicon 4.0L 2005 manual trans here, so YMMV. I only removed the exhaust from the manifold and let it drop down. I was easily able to move it around enough to slide the oil pan out. I didn’t pull the starter either, it wasn’t an issue. Would do the same thing again, since I was on jack stands with limited room.
Sorry for the long post about the one piece seal, I always thought the 4.0L and 2.5L were similar, I know they use the same pistons and many other parts. Did not mean to waste your time.
Most manufacturers switched to the one piece rear main in 1986 I guess Jeep chose not to.
Good Luck with your seal fix.
Most manufacturers switched to the one piece rear main in 1986 I guess Jeep chose not to.
Good Luck with your seal fix.
I received this note from the forum today but it does not show up in this thread? "geebus. Every step of this job has a new annoyance. Any tricks to getting the seal out of the bearing cap?"
You need to be careful what you use to remove the seal from the engine block or you can hit and damage your crankshaft seal surface. That surface needs to be scratch and damage free or you will have a new leak even with a brand new seal installed.
I would use a piece of wood, maybe the size of a pencil, tap the wood on your seal, the wood will not damage the crank or the seal groove. As you tap the seal should start to rotate out. once you get about 3/4 inch of the seal protruding on the opposite side from where you are tapping grab it with good pliers and pull it out.
A tip, you can loosen the main bearings very slightly which will let the crank droop a little and give you extra clearance to remove and install the new seal. Follow exact factory torque recommendations when you torque the main bearings including your rear main with the new seal. Follow the torque map as recommended. Usually starts in the middle bearings and works out to each end as you torque. Do this in several steps to evenly bring the crank back to its original position. Maybe 20 ft pounds, then 35, then 55 till you get to the factory spec. I would need to look up the factory spec on this engine.
You need to be careful what you use to remove the seal from the engine block or you can hit and damage your crankshaft seal surface. That surface needs to be scratch and damage free or you will have a new leak even with a brand new seal installed.
I would use a piece of wood, maybe the size of a pencil, tap the wood on your seal, the wood will not damage the crank or the seal groove. As you tap the seal should start to rotate out. once you get about 3/4 inch of the seal protruding on the opposite side from where you are tapping grab it with good pliers and pull it out.
A tip, you can loosen the main bearings very slightly which will let the crank droop a little and give you extra clearance to remove and install the new seal. Follow exact factory torque recommendations when you torque the main bearings including your rear main with the new seal. Follow the torque map as recommended. Usually starts in the middle bearings and works out to each end as you torque. Do this in several steps to evenly bring the crank back to its original position. Maybe 20 ft pounds, then 35, then 55 till you get to the factory spec. I would need to look up the factory spec on this engine.
Yeah i ended up getting it out so deleted post. I just didn't want to hit it with anything that could scratch anything. Ended up putting it in a vice and using a piece of wood like you mentioned.
Getting ready to tackle this job. From my old chevy days - we would offset the 2 piece rear main seal slightly so that the mating edges of the seal were in the groove ... slightly offset from the parting line that is the main cap to block surface. I've seen others report of doing this for the 4.0L engine too ... but surprisingly, nobody in this thread. Why not? This will only work for the RMS that does not have the legs on it.
https://www.cherokeeforum.com/f2/any-truth-rear-main-seal-205348/
Here's an example from a 455 ...
https://www.cherokeeforum.com/f2/any-truth-rear-main-seal-205348/
Here's an example from a 455 ...
As long at the RMS doesn't have the tabs on it I don't see why this wouldn't work. I only think it could help without hurting at all.
Fel-Pro is a major source for sealing tips. They advise you to offset the seal just like in your picture for the 455.
They also say to add a film of silicone on the parting lines, the end of the seal where the two halfs will meet.
A film is all that is needed, if you put a glob on it will cause other issues.
They also say to add a film of silicone on the parting lines, the end of the seal where the two halfs will meet.
A film is all that is needed, if you put a glob on it will cause other issues.
I agree. But, it's just weird that nobody in this thread has mentioned it yet ... and this is sort of old school knowledge that has been around for a really long time (with regard to the 2-piece seals).
Pcleaners2
TJ Enthusiast
Well considering I’ve done it the other way twice and it leaked like a siv I guess this way sounds better. Do we still need anaerobic on bearing cap edges then ?
Definitely. The anaerobic sealant is a necessity.
I actually just called Fel-Pro and they really weren't that helpful. The tech said that you could rotate if you want, but this seal doesn't require it (some Fel-Pro seals have it in their instructions). I asked about RTV on the ends of the seal because some actually recommend a 'thin film'. He said I could if I wanted to.
So, the only for sure thing is to use a small amount of anaerobic sealer on the metal cap to metal block mating surface along that outside edge (not much according to the FSM). I would also make sure to seal up the oil pan in those areas too - using the Permatex Black Oil Resistant RTV (in the places the FSM says) .... and DEFINITELY give everything at least 24 hours to cure and bond appropriately.
Pcleaners2
TJ Enthusiast
Amazing. Followed this and made a video on it. My rig was leaking A TON, as in the full contents of the engine every 500 miles, now, its dropping 1 drop every now and then. One of the larger bolts holding in my oil pan was stripped so I feel like once I replace that, it will stop for good. Thanks for the amazing write up!
Pcleaners2
TJ Enthusiast
I wrote this write up back in 2008 and posted it on my website when I was doing the very rear main seal job that you see on the pictures.
I still don't have any leaks. *Knock on wood* It has been 12 years.
Something worked!
Last edited:
OP
Fixed that! My apologies!
Glad to see your still around and still into TJs from what I can tell
Pcleaners2
TJ Enthusiast
Yup this is the one I followed both times and have still leaked both times. Must be something different as I have the newer type seal in a 2001. I’m going to try and follow someone who said to rotate the seal so it’s offset and try that way. Your write up is good just for some reason didn’t work for me
thanks
TJ2
TJ Expert