[84 400]

If it is the rear main seal I did this a few months ago in the vehical.
I did mine on the 1956 willys wagon that I have in my sig. It now has a 350. Well when I installed the 350 I did not replace the rear main thinking it was fine since it did not leak... what a mistake!!!!

Anyways here is what is involved. Fist had to drop the oil pan. Then the oil pump and lower pump drive shaft come out. then the rear main cap. Then you need to remove the rear main seal or what is left of it. The bottom half is easy enough because you can just pop it out of the main cap. the upper portion sits between the crank and the engine block and is not so easy. You can utilize a set of needel nose plyers and abrass drift or a flat head screwdriver. The trick is to rotate the seal with out scratching the crank shaft surface. once you get one end of the seal rotated around you can grab it with the needle nose and work it around the crank shaft until it is all the way out. Sometimes rotating the motor can aid in this process. This by far to the most time for us. Next you want to try your best to de bur any of the seal contact areas.

The instillation can be tricky. remember your on you back and the area is quite tight so after fighting with it it can really wear at your nerves. I actually when through 2 rear main kits doing mine because when installing the upper seal I rushed and ruined it. I used the Felpro rear main seal kit and it comes with the two peace seal and the oil pump drive connector as well as a small plastic shoehorn used to aid in the instillation of the seal. Once started the upper seal slowly rotates around. It is important to go slow as any binding could ruin the seal or could indicate that some of the old seal is left in the area. Once installed you can make the ends flush or "clock" the ends where the upper and lower seals meet. Some do it the flush factory way while others say that clocking prevents leaks. I did mine flush and have no leaks. A dab of ultra black high temp RTV at the two points where the upper and lower parts of the seal meet and you are ready for re assembly. I made sure to put a good amount of assembly lube inside the rear main cap to aid in initial lubrication when starting the motor. I rotated the crank slightly to make sure it was seated properly while tightening the rear cap. The cap was torqued to 80ft as per torque specs but these could vary depending on motor. next I cleaned the oil pickup screen with brake parts cleaner and reinstalled. It is important to make sure the drive shaft for the oil pump is in and that you replace the old plastic coupler with the one found in the kit. Then torque the oil pump to the rear main cap per torque spec mine was 25foot pounds.

This is a good time too clean your oil pan of any sludge (mine had a lot) and gunk. Also I opted for a 1 piece oil pan gasket from felpro. It cost 30 dollars but is reusable and is built very well. The one piece pan gasket comes with longer mounting hex head screws for the oil pan as well as these neat little plastic clips with arrow head which hold the pan up while you put the bolts in.

Then simply refill with oil and crank the motor over a few times to build pressure in the pump before starting the motor up.

The felpro directions for the rear main seal kit and the one piece gasket are very clear and well written!!!!

Total cost:

rear main seal kit from felpro was aether $12.00 or $15.00 i can't really remember but i would suggest getting two in case you mess one up (you can always return one but it sucks to have to stop and run to the store)

One peace oil pain gasket kit from felpro $27.00

and you will need a torque wrench for the main cap bolts.

Took me about 3 hours to complete the job because I took my time and it was my first time doing a rear main in the vehicle. Don't get me wrong it is defiantly not a fun job but not as bad as i thought and my old seal was really stuck in there which was the part that took most of my time.