Review on Enhance Engine Performance with Fel-Pro BS 40183 Rear Engine Main Seal Set by Frank Bruton

Unsurpassed quality. This is a manufacturer of seals for Jeep Wrangler TJ as well as many other vehicles. The quality is definitely there. Installing the rear main oil seal on a 4.0 liter engine can be difficult but there are many installation reports online. And hey, you don't have to pull the transmission to get to it. However, you *really* have to pull out the entire exhaust system, which is a big PITA. You get to this by removing the oil pan, and the exhaust only gets in the way of this project. However, this allows you to really inspect the underside of your engine and you can walk over the oil pan and find metal shavings or shavings (or big chunks!). I highly recommend replacing the RMS with a 4.0L if you need to replace an oil pan gasket and vice versa. Read about it and watch some YouTube videos and you shouldn't have any real problems. Removing the old top half and installing the new one can be very difficult, but again, EXPLORE and you'll be fine. It may seem like a daunting task, but if you're fully prepared and know what to do, you'll be fine. This Fel-Pro gasket is one of two or three I've ever considered for use on my engine. Don't be a fool and buy a cheap RMS. This is one of the few spots on our 4.0 liter engine that is prone to leaks. Get a good one and INSTALL IT YOURSELF so you know it's done right and your street stays clean! Also, keep an eye on the valve cover gasket, as the rearmost bolt tends to leak if improperly installed. If you make an oil pan gasket, a rocker cover gasket, and the rear main gasket, you'll have a happy engine.