AW4 year changes?

1997 XJ 4.0L, NP231; I'm shopping for a new AW4 (due to my own F-up) and found one on Amazon, but they list it for only 1994-1996. Why those specific years? I thought the XJ AW4 was only changed in 1991 to the 23 spline output then it was the same until 1998 when the TCU was changed.

Anybody confirm this? Is it a different TCU?

Part# S-4810179 keeps coming up for the '91 and later AW4's.

There are minor differences, IIRC there is an additional sensor in the later model AW4? I know there is in the later t-case but not 100%. You should be fine with any 23-spline

Somewhere around here I have an AW4 FAQ... regardless, only 97 trans will be 100% bolt in for you due to a stupid chrysler wiring harness connector, but you can use any 91 through 97 trans if you don't mind doing extremely minor wiring harness splicing, should take no more than 20 minutes with a crimper and butt splices and that's assuming you want to make it look perfect and tape the harness back up exactly how it was. It's all connector swaps on the trans side, no engine bay harness modifications needed.

98-01 will also work for you but it'll require some parts swapping off your old transmission.

Thanks. Also, do you know if those wires are the same color or will I have to do some wire chasing?

Everything you ever wanted to know about AW-4 swapping by kastein.

No need to be humble, its one of the best Tech threads on .

Moses Ludel personaly just shot me that link to Kastein's link. Thanks for the help.

you're kidding me. I had no idea it was that well regarded, it's not even complete.

Regarding break-in procedures you PMed me about - my PM box is full (again) so I'll respond here. I unfortunately have no idea how to break in an AW4, I've never owned a new one and therefore never had to break one in. What you said sounds good though, I'd probably change the fluid at a few thousand miles to pick up any leftover material from machining/assembly and go easy on it for a while.

Make sure you have adequate cooling and flush out the fluid lines to the cooler before installing it - the quickest way to kill any auto trans is to run crappy fluid or fluid contaminated with debris from the old trans in it, and the quickest way to end up with crappy fluid is to overheat it.

It appears that unit comes with a new torque converter installed and strapped in place for shipping. I'm not entirely sure if you should fill it before installation but I like to - if you do, make sure it's properly fully seated in the transmission again before installation, which is easiest with the trans standing on end.

I see the part number you listed in my 94-96 XJ parts catalog, so it'll definitely fit a 97 with the minor wiring mods I mentioned. IIRC the colors are the same (it's just 4-5 wires - 3 solenoid drive lines, an output speed sensor signal line, and possibly a ground) but you should check the relevant FSMs to make sure. Various years have the wiring for the VSS, rear O2 sensor, and/or transfer case indicator lamp switches in the same harness so depending on how it's put together you might need to splice different things. I'm not too clear on it (aside from having done it once - it wasn't that difficult) or what the exact year splits on that stuff is, but if you can post some pictures of the harnesses once you have the old trans out and the new trans sitting next to it I can probably tell you exactly what to splice, either that or you can figure it out yourself, it wasn't really too hard to deduce from how it was set up.

You will need to swap your NSS or a new 97-01 replacement onto the new trans, also - the 87-96 one is different and not compatible with the 97-01 electronics.

Thanks. Yeah, apparently your knowledge is trusted by the Jeep God, himself. I ended up on his website and he has "contact Q&A". http://www.4wdmechanix.com/. So much great info.