Engine swap

[HPI_Savage25]

Ok here is my dilemma. I have a 1990 XJ with the 4.0 and automatic. I also have a 1989 XJ that is 2wd but with the 4.0 and a 5 speed. My 1990 is leaking oil at te rear main and it's been replaced. Can't seem to get it to stop leaking so I am wanting to swap motors between the two. What all would I have to buy and would the swap work without any major changes?

[4.3LXJ]

It will work. You will have to replace the flywheel with the flex plate. You might want to inspect the old one closely for cracks, which is common. A new one might be a good idea.

[LizardRunner]

Like Steve says, pretty straight forward R&R just change out the parts for the auto tranny to hook up. And Like he said, either check the flex plate really well or just put in a new one. Oh and be sure the bolts are loctited when you install the flex plate so they can't come loose very easily. I'd use the red loctite for those bolts.

[HPI_Savage25]

Alright awesome. So just swap the flex plate over if it's ok or get a new one if needed. Hopefully the other motor is ok and doesn't have a cracked head. Jeep is in the shop now to take a look at the oil leak again. If it still leaks after this ill do the engine swap. Thanks for the info!

[LizardRunner]

I believe you could also swap the heads. It's more normal to have a broken gasket than a cracked head UNLESS you heat soaked your engine.

[HPI_Savage25]

The other XJ kept over heating. Shop said it needed a new radiator and it needs a steering column. After flushing the radio for a few weeks we believe it is good now but as we can't drive it we aren't for sure. I figured the worst I just have to swap heads on it and hope that's it

[LizardRunner]

Sounds like you have the plan are moving into action.