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Really dumb question...just need confirmation.

Stallacrew

NAXJA Forum User
Location
Cullman, Alabama
My Jeep story:

16 years old I get my burgandy (purple/brown) 1989 XJ. Love it, and can't ask for more. Hit a car, replace radiator, and header panel etc. Hit stump in ditch, totalled it. Ended with 134k.

17 years old, get my black 1993 ZJ, love it great power, hauls wonderful, has 5.2L and gets 10 mpg if lucky. Drive for 4 years. Still have, has 147k.

20 Years old, get 1990 blue XJ with 234k. Bum engine but only cost $600. Swap 89's engine into it; drive from 21yo to 22 yo. Stroke the bum engine ( bad rod bearing) and this brings us up to current.

The 1990's AW4 with 230k on the clock is starting to suck. I know the AW4 from the 1989 is good ( or was when it was parked 4 years ago). However when the thing got totalled (we kept it and didn't file it on insurance) and it developed a leak in the roof/door area where it crinkled . F'ed up the interior and I started to take it all out. while taking out the dash I pulled the TCU I think. Little yellow box and also all the shit under the dash on the drivers side

So when we go to take it and have the engine swapped, the 89 XJ cranked fine, and rolled fine on level ground under it's own power. However, getting it on the tow dolly, I had to drop the shifter to 1st to get it to move up the incline. It was really taching out in drive, but wouldn't go up, and did fine in 1st.

Would this indicate that the transmission is fine, I just unplugged what controls it, or what?

I figure the 1989's tranny is still good, it just wouldn't load on the dolly because it didn't have its computer.

Is this right?

Sorry for the lengthy explaination, however you now know my entire Jeep history.

--Alex
 
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I think that little yellow box is the "brain" for the cruise control - you'll find the TCU under the glove box on the passenger side (it's retained by two studs into "wings" on the box, and the box is steel.)

You'll want to clean out the AW4 - use a good flush for the first 5K or so, and really blow it out. If it's sat for the last four years, chances are good there's some varnish buildup in it.

Also, make a note to yourself that you've swapped it - and the transfer case. Apparently, the AW4 changed output splines for 1991 - went from a 21-spline output to a 23-spline. I doubt there are significant differences between the two for service parts, but why take chances? I don't have my notes open to check...
 
So you're saying if it was working before I took everything out, it should be good now other than a thorough flushing as long as it will match up with spline count?
 
Stallacrew said:
So you're saying if it was working before I took everything out, it should be good now other than a thorough flushing as long as it will match up with spline count?

Yah. Take the transmission and transfer case as a single unit, note the swap (you do have a notebook for rig mods, don't you?:wave: :doh: :lecture: ) and drop it in. The rest should go in easily - you can swap the NSS back and forth if necessary.

Change the fluid, and dump in a pint of B-12 Chemtool with the new fluid. Run it for about 5,000 miles (make sure to get it good and warm a few times to break up the varnish that surely has built up,) and change it hot to get as much out as possible. That should see to most of the stuff.

And, it's easier than taking the thing to bits and cleaning it all by hand (not as thorough or as satisfying, but easier. What can I say? I like to work on things...)

OK - just re-read. The 1990 will probably be a 21-spline as well, but you should count to make sure (I keep seeing that the AW4 changed when the HO engine rolled out in 1991, but the manual went from the 21-sp BA-10/5 to the 23-sp AX-15 in 1989.5, and I thought the AW4 changed at the same time. It would make sense if it did, but that don't mean much... Noviry v proviry - we trust but we also verify.)
 
You need that box plug in for the 89 tranny to work. I found that out in my 89 when I had it unplugged to work under the dash then had to go for parts. I didnt plug it back in and I got no where fast. I pluged it back in and all was fine.
 
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