Rear Main Seal

are you SURE it's the rear main?

$300 dosn't sound bad - I think the 4.0 is a 2 piece. Need to drop the pan and take out the main bearing cap. and push the old seal out and the new one in. not really a fun job.

I did mine recently and on 2 other motors have never been able to get the upper piece out. on this one I could not get the top out either. and it still leaks. Never had a problem on the other trucks.

so just for giggles I called jeep to see what they charge and

460$ will get you a new rear main installed. just got the price today... so 300 is better than that.

Quote from "BDLSTOY"

I stopped over to my mechanic friends house and thats what he told me. Its leaking where the bell housing is connected to the motor. I'm pretty sure its the rear main seal.

just make sure it's not coming from above (valve cover or something equally stupid) and ending up at the bell housing...

how bad is it leaking? - I put one in the ford when I had the motor out, it's leaking. I must have drove it in too far or not far enough. The bottom of the bell housing is wet, but it dosn't drip.

Rear mains are a pain. On a 258 you have to upbolt the passenger side motor mount and jack up the motor to expose 2 oil pan bolts. Once you drop the oil pan you have to remove the rear main cap. The lower half of the rear main rests in a groove in that cap. The upper will require carefully driving it out. I think they usually use a punch and mallet. But being made of rubber, the seal will absorb a lot of the striking force. Once you get enough driven out you may be able to grab the end and yank it. I think there is a tool that makes the job a lot easier. From what I've read, putting the new one in is a lot easier. I think you use dish soap so it will slide in easier.

I've only done them during a rebuild with the engine remove (which was a lot easier).

Quote from "Slimer"

Rear mains are a pain. On a 258 you have to upbolt the passenger side motor mount and jack up the motor to expose 2 oil pan bolts. Once you drop the oil pan you have to remove the rear main cap. The lower half of the rear main rests in a groove in that cap. The upper will require carefully driving it out. I think they usually use a punch and mallet. But being made of rubber, the seal will absorb a lot of the striking force. Once you get enough driven out you may be able to grab the end and yank it. I think there is a tool that makes the job a lot easier. From what I've read, putting the new one in is a lot easier. I think you use dish soap so it will slide in easier. I've only done them during a rebuild with the engine remove (which was a lot easier).

Yeah, I've never been able to get the upper part out, with a punch. but I never had a problem with it leaking after only replacing the bottom (2 other motors) but this one just wants to be a pita! I'm thinking it might actually be the blowby, and pcv system. I am going to take off the valve cover and clean things up. if I still have an issue then i will drop the pan again, and loosen all of the main bearing caps to lower the crank down a little in order to get the top out too. we will see.

screwed up my cutting and pasting the first time. the post reads better now.

I will be removing and cleaning up the valve cover a pcv system

If you think it's blow by check your PCV valve and make sure it is getting suction.