If you own a Jeep vehicle with a 4.0L engine you will most likely run into the problem of the rear main seal leaking oil. This will make a mess on your driveway and will get oil all over the undercarriage of your Jeep. I have a 97 wrangler with 70,000 miles and have had to have the seal replaced twice. I called around and got quotes ranging $650 to $750 to do this work. I don't have the money to get it done so I decided to do some research and see what is involved in replacing it. I do a lot of my own work on my Jeep but when it comes to more than basic engine work I tend to stay away. So I found out that all the parts would only cost $57 and it seemed not to be that much work. It took 2 days to get this project done and saved myself about $600 or so.

These are the things I needed to buy to complete this project. There is the oil pan gasket, the rear main seal gasket, some high temperature gasket maker, and a gasket scraper.

The first step is to drain the oil from the pan. If you have the stock exhaust, your pipe will cut in behind the oil pan, this piece of pipe will need to be removed. Unbolt it from the catalytic converter and from the stock manifold to get it out of the way. On my truck I have after market headers and the pipe goes in front of the oil pan then back to the cat and muffler. This lets me take the oil pan out without having to remove the pipe.

Next begin taking all the bolts out of the oil pan, make sure you mark where they all came from because there are 3 different types of bolts and you will need to put them back later.

Once the pan is out remove the gasket and scrape off all the residue left. Now is a good time to clean the oil pan out to remove any sludge.

Scrape the old gasket material off the block and clean all around the engine. Some Jeeps have a bearing brace (the flat bar on the bottom of the engine) so if you have one like in my engine this needs to be removed. While the pan is off check the timing chain (at the very front of the engine) if there is more than 3/4" slack in it you should probably replace that as well.

When you take the brace off clean it and set it aside.

Check your oil pickup and other parts of the engine and make sure every think looks ok. You need to remove the last bearing cap all the way to the right in this picture. These bolts are pretty tight so you will probably need a breaker bar to get them loose.

Replace the bottom seal in the back of the bearing with the new one you bought. Be very carful not to damage the bearing. Coat the bearing in motor oil before reinstalling.

Replace the top seal in the block next. You can see it in here, it is the orange thing on the left and right of the bearing. This picture was taken before I removed the brace and bearing. Just use a small screw driver and hammer to knock it out from one side. Once you get it out replace it with the new one, just make sure you put some motor oil on it to make it slide in easier.

When the seals are replaced you can start putting the engine back together. Pretty much just do everything in reverse. When installing the rear bearing make sure to put some silicone gasket maker on either end of the seal like it says on the seal instructions. Put the bearing in place and tap it with a hammer to seat it then torque the bolts to 80 lbs. Next reinstall the brace if you have it and torque the nuts to 35 lbs. Make sure the oil pan and the block are clean from gasket debris and install the gasket on the pan. Put a little gasket maker on the corners in the rear and the front of the pan as the gasket instructions say. Slide the pan into place and bolt it back in. Change the oil filter and fill the engine with oil after making sure everything it tight.

It took me about a total of 6 hours to do this job over 2 days. I could have done it quicker but I was taking my time and drinking some beers. I have driven the Jeep a couple of times and have had no problems or leaks. Email me if you have any questions.