MJ 2.5 to 4.0 motor swap

I tried searching on this and could not come up with anything specific. Doing this on a friends truck.

What we have

1990 MJ 2.5TBI 4-speed good straight truck but the motor sounds like it has gravel in it.

1989 Wagoneer 4.0 Automatic that was wrecked and poorly pieced together with another jeep. Its a pile of crap in other words but it runs perfect.

Tools and equipment is not a problem at all. Mainly just wanting to see what all we will need. The reason for this swap is there is $750 tied up between the MJ and the XJ. Its hard to find a 4.0 4x4 MJ around here, and the options around the country are pretty poor as well.

Thanks in Advance for any Info. Like I said they run and drive but we just need to make that MJ a 4.0 .

Clark

MODs, if this needs to be in OEM please do so.

Get yourself a 89 or 90 Factory Shop Manual (the 2 years are essentially the same thing), take LOTS of good quality digital pictures and carefully mark all the parts as you remove them. Most everything needs to be swapped over, wiring and all. You might even just gank the whole dash as an assembly instead of the individual parts. And you'll still need a rear driveshaft. The 2.5L axle will have 4.10 gears so keep it and grab a 4.10 Dana 30 from the junkyard.
Jeep on!
--Pete

ComancheClub.com

Pete M said:

Get yourself a 89 or 90 Factory Shop Manual (the 2 years are essentially the same thing), take LOTS of good quality digital pictures and carefully mark all the parts as you remove them. Most everything needs to be swapped over, wiring and all. You might even just gank the whole dash as an assembly instead of the individual parts. And you'll still need a rear driveshaft. The 2.5L axle will have 4.10 gears so keep it and grab a 4.10 Dana 30 from the junkyard.
Jeep on!
--Pete

ComancheClub.com

Click to expand...

Actually, we have already been into the rear axle. The reason it was so cheap was the differential pin was broken. How a 2.5L breaks the drive pin I have no idea but it was shattered. Much to our surprise it has 3.55s. Maybe its because of the 4-speed with no OD?

D'oh! Forgot about that. Yeah, most 2.5L/4speeds had 3.55s.
Jeep on!
--Pete