Auto trans swap ?'s

[IDXJ]

A friend of mine has an '87 XJ and the trans is toast. I located an overdrive trans (AW4?) in a "92 XJ that is being parted out. The "87 has the 3 speed and the '92 has the overdrive. Are there any issues with the swap he needs to be concerned about? He is swapping the T/C also because of spline count and, the shifter. Both of mine are 5 speeds so, I am not in the know about the auto's. Thanks

[Pete M]

What engines are in the 87 and 92?

[IDXJ]

Both 4.0's

[Pete M]

Then the 87 isn't a 3-speed. It's a 4-speed AW-4. They are both AW-4s. And I do believe they are swappable, but I'm not much of an auto expert so wait until someone can give you confirmation on that. After the swap, be prepared to try and track down why overdrive wasn't working in the 87. I think overdrive is computer controlled so there may be a fuse blown or maybe the trans computer is fried. Or it might be a problem with the trans itself Once again, I'm out of my little bubble of knowledge so I'm not sure what you should check first.

[IDXJ]

So the '87 is AW4? I admittedly don't know about the auto's and have only been in the Jeep once but, the shifter only has 3,2,1. No indication of overdrive and, no O/D button anywhere that I saw.

[Pete M]

I think OD is controlled by the little trans computer.

[IDXJ]

Should be a pretty straight forward swap then I guess. Thanks

[Pete M]

Maybe. I do know there's a cutoff where it becomes very hard to swap, but I think that comes later on, like in 97 or something.

[mvusse]

I have an 87 4.0 auto, and it's an AW4. Shifter pattern is

 

P

R

N

D with a circle (overdrive)

3

1-2

[reson46]

So the '87 is AW4? I admittedly don't know about the auto's and have only been in the Jeep once but, the shifter only has 3,2,1. No indication of overdrive and, no O/D button anywhere that I saw.

 

Is the shifter out of something else? All the automatics for the 4.0s in XJs/MJs should be AW4s. If the automatic and 4.0 in the '87 are stock it should be an AW4.

 

If it is an AW4, the '92 AW4 will swap in with one exception - the output spline count. In '87 the AW4 had a 21 spline output, '92 will be 23 spline. You could swap the transmission and transfer case from the '92 or you could swap out the transfer case input of the '87 to a 23 spline input.

 

Willy

[pingpong]

Pong who is a 90 mj had a 23 spline output np231.

[Motion Offroad]

Mid 1990 was the conversion from 21 spline to 23 spline. Also be aware that the 23 spline input NP231 TC (if thats what he has) will not have the stuff for the vac. disco on the axle. So if he has a vac. disco axle he will have to do something about that to control the 4wd function as the TC will not be able to do it.

 

The TCU monitors throttle position, ground speed, and shift lever position (switches in the console) to select the gears appropriately. It also monitors position of the POWER/COMFORT switch (for those of you who have it) to change upshift and downshift points and TCU lock parameters.

 

Here is a link to the AW4 manual that may be of some help during the swap.

http://www.greatlakesxj.com/tech/AW4_manual.pdf