newer AW4 into older XJ swap....help!

I tried several searches, reviewed the FaQ page and cant seem to find an definitive answer....

Here's my problem..
My 89 XJ limited has a slipping trans and I am fairly sure it is going out...drives along fine then all of a sudden it slips and the tach jumps from 2k to 4k for a min or less then back to normal for a few miles then slips again.... I want to fix the jeep but have no money for a tranny rebuild or even repair.

My 93 police package XJ, which has severe, severe, rust, has a very strong drive train.

Both XJ's are 4.0L, AW4, NP242 optioned w/ the 93 being a H.O.

Here's my question...
Will the 93 AW4 and NP242 swap directly into my 89? Are there any known issues or foreseen problems? The 93 is close to being scraped/parted and the 89, with the exception of the bad tranny, is in good mechanical shape.

Thanks guys in advance for the help!

it should bolt right in.i don't think any of the electrical plugs are different.

the spline count is different

use the 93 trans and transfer case. the early trans is 21 spline. the 91 and later is 23 spline.

i know about the different spline count...I was more interested in any electrical issues. Ill swap the aw4 and transfer case from one to the other. Get a working trans and stronger spline count to boot...

Electrically an 89 and a 93 are exactly the same. Might have to swap the switch and vehicle speed sensor / speedo takeoff on the transfer case but it should just bolt up.

I believe the electrical connectors will just plain plug right in, if they will not, the wire color codes should be the same. Post up if you have any difficulties and I will see if I can figure it out.

The worst thing you will have to deal with is that you might have to swap the throttle valve cable, I'm not sure if the end that connects to the throttle body / throttle bellcrank on the 89 is the same as the one that connects to the throttle body on the 93.

Out of curiosity though, have you checked the fluid level and made sure the lines to the cooler aren't leaking?

You should use the flexplate and CPS from the 89. Make sure you install the torque converter in the transmission and then bolt the transmission to the engine block, then bolt the torque converter to the flexplate. Bolting the torque converter to the flexplate and stabbing it into the transmission is almost guaranteed to break the tranny pump input gear and mash up the splines on the input and reaction shafts.

fluid is full, no noticeable leaks. It just slips...

hmmm... any crimped spots in the cooler lines that could reduce pressure/flow? Check em, especially immediately above the passenger side upper control arm mount on the axle / below the passenger side engine mount. If you've flexed it out before you may have smashed the lines flat there.

If that isn't it, I'm all out of ideas aside from replacing or rebuilding the transmission.

bone stock xj, so I'm almost positive it hasn't been wheeled....but ill check the lines above the pass UCA.