The original writeup I used for this is from GN T-Type.org. However, there are a few things along the way that I think are useful for a Jeep owner with a 225 so I’ve adapted that write-up, with full credit of course. This was not my original write-up, and I had quite a bit of input from forum members along the way.

Stuff you’ll need

1. New Neoprene rear main seal
2. Black or Ultra-Black, O2 sensor safe RTV Sealer
3. New oil pan gasket kit, includes oil pick-up gasket

Tools you’ll need

1. 1/2″ drive ratchet, 5/8″ socket for rear main cap bolts use a 6-point socket on rear main cap bolts!!!
2. 1/4″ drive ratchet, 1/2″ & 7/16″ socket for oil pan bolts
3. Torque wrench (1/2″ drive, 0 to 150 lb/ft min)
4. Needle Nose pliers
5. Rubber Mallet or “soft” hammer
6. Rags & Acetone to clean surfaces
7. 1/4″ Oak dowl
8. Small screwdriver and/or putty knife to clean off old RTV sealer
9. Lisle Sneaky Pete or drywall screw

Procedure

1. Drain oil and remove oil pan, flywheel cover, and oil pickup.
2. Start to loosen the main bearing caps. Start with the rear cap, remove it entirely. You’ll likely need a breaker bar to break the bolts loose, FSM torque specs are between 80-110 ft. lbs. Use the bolts to wriggle the rear main cap out, it’s tight, so using the bolts in the cap after they’re removed, use them as levers to remove the cap.
3. Loosen other main bearing caps, now isn’t a bad time to remove them and inspect the bearing inserts if possible.
4. Remove the lower 1/2 of the seal from the rear main bearing cap and any RTV that may be on the cap.
5. Install the new seal, the instructions will have the proper orientation, the Fel-Pro I had required that the large face be facing toward the front of the engine. It will be obvious which face this is. Be sure to keep the cap and bearing clean!
6. Depending on your Jeep the upper half of the main seal can be easy or difficult to remove. Mine was difficult. Be carefull not to nick or scratch the crank when working on it. Sometimes you can just grip the seal with needle-nose pliers and pull it out. I wasn’t so lucky. Mine took a lot of work with the corkscrew that came with the Sneaky Pete, though Sledgehammer from the forum recommended a drywall screw or other suitably coarse screw. Remember, BE CAREFUL around the crank.
   • With mine it required some persuasion. I used a 1/4″ oak dowl and used a small hammer to drive it in on the passenger side and the corkscrew on the drivers side to pull it out in about three pieces.
7. Once the old seal is out, clean off any RTV sealer on the block. Lube up the other half of the new seal and slide it up into the block with your thumb–make sure it is facing the right way! If it is going to be a bit before you start the engine, use grease to lubricate the seal.
   Note: A good idea is to insert the new seal so that the mating faces of the new seal are not lined up with the mating faces of the main cap. About a 1/4″ extra rotation one way is enough.
8. Put a thin coat of RTV sealer on the cap-to-block mating surface of the main cap and on the chamfered edge. Lube the main bearing with clean oil or grease. Make sure the bearing is seated in the cap. If needed push the bearing into the cap and make sure the tang is engaged in the slot in the cap. Install the cap back in the block and install the bolts and finger tighten.
9. Torqe all the main bearing caps a little at a time. Don’t go straight to 80-100 ft. lbs., tighten gradually to the final value.
10. The side cavities need to be filled full of RTV sealer. I did not use the rubber inserts that come with the new seal; just use RTV sealer. Permatex makes a “Powerbead” can that has the gasket maker in it, just cut the tip and follow directions. It works well for this. I used the Ultra-black to fill the galleys. Let the gasket material set-up for 24 hours before starting engine.
11. Reinstall the oil pickup, and pan.
12. Fill with fresh oil and fresh filter.
13. Start engine, be sure oil pressure is good. If no oil pressure, remove oil pump cover and pack with petroleum jelly to prime pump.