Rear Main Seal and Oil Pan Gasket

**tamu83cj** · 11-20-2009, 09:09 AM

I have a leak that is one of the two, but not sure which. I have been told it is a huge job to change the Rear Main, but wanted to see if anyone has a good story to tell about doing it yourself?

Thanks,

**Mike Romain** · 11-20-2009, 09:17 AM

Well for a Jeep 6 cylinder 258 ci engine, that leak is commonly caused by a leaky valve cover that runs down the back center of the engine and drips where you describe. I don't know if your engine is the same as a Jeep engine.

To test for this, we get the engine running and the take a clean rag and rub the back of the engine head below the valve cover gasket. If we find oil, we have the leak.

If it is either the pan or rear seal, on a Jeep engine we can fix both from down under, the engine doesn't have to come out. The Jeep engine has a two piece rear main that can be pushed out without removing the tranny.

**tamu83cj** · 11-20-2009, 09:21 AM

Mike, thanks for the reply. I think it is the rear or oil pan because the oil is actully dripping out of the rubber boot that covers the clutch. The boot has a rip in it, and the oil is dripping onto the exhaust pipe and smoking real bad.

I will check the valve cover because that would be an easier fix.

If it is the rear main, do i drop the starter, the oil pan and then do i have to remove rear drive shaft and lower the transmission just a little to get to the top portion of the seal?

starfire340 · 11-20-2009, 12:31 PM

Hi Tamu83...I just got done with this on my 83 about 2 weeks ago. I removed the starter. I also had to remove the RH (passenger side) motor mount to get to the pan bolts under there. I simply blocked up the bell housing with the floor jack and left myself enough room to work. you will have to remove the tubular crossmember brace directly under the oil pan to drop the pan down. Driveshaft removal front or rear is not necessary. Like Mike said, upper rear main simply pushes out. I had to get it started with a small punch being VERY careful not to damage any of the surrounding surfaces (a brass pin punch would be better) After "lubing" up the new seal it simply follows the countours of the machining and rolls right around the crank into place. Pay attention to the direction of the lip on the old seal to make sure your new one goes in the same way. I would also recommend spending the extra $$$ to get the new one piece Felpro brand pan gasket. It is blue silicone with individual steel rings around the bolt holes. I have had my pan off twice for various reasons since I initially installed it and am real thankful to be able to reuse it, plus it leaks little if any oil. This really isn't a big job, just dirty,oily and time consuming.
Good Luck! If I can be of any other help, just yell!
Mark

**Mike Romain** · 11-20-2009, 12:44 PM

Quote:

Originally Posted by tamu83cj

Mike, thanks for the reply. I think it is the rear or oil pan because the oil is actully dripping out of the rubber boot that covers the clutch. The boot has a rip in it, and the oil is dripping onto the exhaust pipe and smoking real bad.

I will check the valve cover because that would be an easier fix.

If it is the rear main, do i drop the starter, the oil pan and then do i have to remove rear drive shaft and lower the transmission just a little to get to the top portion of the seal?

So I will figure you are a computer tech and actually do have a Jeep 258 engine in there instead of a 256 eh?

The rear main seal is in front of the flywheel and as such should leak down the oil pan, not out the tranny bellhousing, but oil can do strange things..

Have you checked the tranny oil level?

I sure would check it up top carefully and I believe the other poster covered the fix pretty well.

**tamu83cj** · 11-20-2009, 01:16 PM

I'm a typing expert, never hit the wrong button, so i'm sure it was the keyboard.

I made the change, thanks for the catch.

Pog · 11-20-2009, 05:01 PM

Quote:

Originally Posted by starfire340

Hi Tamu83...I just got done with this on my 83 about 2 weeks ago. I removed the starter. I also had to remove the RH (passenger side) motor mount to get to the pan bolts under there. I simply blocked up the bell housing with the floor jack and left myself enough room to work. you will have to remove the tubular crossmember brace directly under the oil pan to drop the pan down. Driveshaft removal front or rear is not necessary. Like Mike said, upper rear main simply pushes out. I had to get it started with a small punch being VERY careful not to damage any of the surrounding surfaces (a brass pin punch would be better) After "lubing" up the new seal it simply follows the countours of the machining and rolls right around the crank into place. Pay attention to the direction of the lip on the old seal to make sure your new one goes in the same way. I would also recommend spending the extra $$$ to get the new one piece Felpro brand pan gasket. It is blue silicone with individual steel rings around the bolt holes. I have had my pan off twice for various reasons since I initially installed it and am real thankful to be able to reuse it, plus it leaks little if any oil. This really isn't a big job, just dirty,oily and time consuming.
Good Luck! If I can be of any other help, just yell!
Mark

What he said.

Rollbar · 11-20-2009, 05:53 PM

I used the one piece gasket and loved it, never leaked. Also put some SUPER 300 on the seal and it never dries and it wont leak.

shok47 · 11-20-2009, 06:15 PM

When i had trouble getting the RMS out, I used a bottle jack and a brass punch to get it moving, simply jack up the punch on the metal of the rms. Was very easy doing that. I spent hours under there trying to hit it. Unfortunately I didnt have a long enough stick to get a good angle.

WayneMeuir · 11-21-2009, 04:42 PM

Do you need to loosen the main caps at all before pusjing the seal out?

Wayne

**Mike Romain** · 11-21-2009, 04:55 PM

Quote:

Originally Posted by WayneMeuir

Do you need to loosen the main caps at all before pusjing the seal out?

Wayne

I have done 3 and didn't have to loosen. I used a brass punch and the engines were out, so I had room to swing a hammer. I Love the bottle jack idea to push it out from under!

redbird2289 · 11-21-2009, 05:04 PM

this job aint as hard as it sounds just a lil tedious. me and my pops did this in the driveway with a floor jack and some tools.

shok47 · 11-21-2009, 11:23 PM

Thanks mike. Yea, I after getting it out so easily with a bottle jack, I am confidant I can do it on a 258 any day now.