Rear Main Seal

[CRM1988]

In the 1990 Mj 4.0,5 Speed is the rear main seal a 2 piece or a 1 piece?

[jimoshel]

2 . 1 upper, 1 lower

[Pete M]

be sure the leak isn't coming from the rear of the valve cover or some other location. You don't have to pull the trans to change the seal in a 4.0, but it's still a huge pain in the butt and there are other leak locations that can look like a rms has blown.

[CRM1988]

Done changed the valae cover gasket and cchecked around the oil filter.

[juan]

check the oil pan gasgket...that could be your problem.

[tbrand]

check the oil pan gasgket...that could be your problem.

 

If you do one job, you might as well do the other. For me, getting the oil pan on and off was more difficult than getting the RMS out (and that was a pain). Parts-wise, both jobs should be <$50 if you already have tools (torque wrench is key on the RMS job).