92 xj with a 98 AW4 and 98 NP321

Ok, so I blew my tranny and could only find a 98 transmission at an affordable price in my area. I got it in and running, but when I went to put the original 92 drive shaft on and found out that the 92 drive shaft seems a bit long. I don't have the money for a hack and tap with a custom drive shaft, but I do still have the 92 transmission and t-case. Do I need to swap the tail housing from the 92 or will I be okay with a slightly long drive shaft?

Was it 2wd and now 4wd?

Someone here should know for sure whether there's a spline compatibility issue, but I'd say if the tail housing can be swapped, you might as well do that and guarantee a good fit. Either that, or see if you can retrieve the driveshaft from the donor vehicle.

its a 4wd, and I know for a fact the rear drive shaft from the donor is gone, as is the rear axle. What I did grab was the front drive shaft. There is no spline issue but like i said it seems a tad long for the case. I think I will just keep my eye out for a 98 drive shaft unless someone can tell me that my wheels are going to fall off if I do that instead of swapping the tail. I like keeping factory stuff sealed as long as possible. The saddest bit of this all is that I only had to swap the transmission because I accidentally filled my transmission with water when I recently swapped engines by pressure washing the engine bay without dropping the tranny.

xeroOTG said:

its a 4wd, and I know for a fact the rear drive shaft from the donor is gone, as is the rear axle. What I did grab was the front drive shaft. There is no spline issue but like i said it seems a tad long for the case. I think I will just keep my eye out for a 98 drive shaft unless someone can tell me that my wheels are going to fall off if I do that instead of swapping the tail. I like keeping factory stuff sealed as long as possible. The saddest bit of this all is that I only had to swap the transmission because I accidentally filled my transmission with water when I recently swapped engines by pressure washing the engine bay without dropping the tranny.

Click to expand...

I know that an AX 15 interchanges between the two styles, since I just mated a 95 box to a 99 TC. Of course there may have been a change between 92 and 95 that I don't know about, but I'm guessing the two are still compatible, in which case, if you're in the mood to do a whole lot of work and take apart half of what you just put back together, you could swap transfer cases. As a bonus, I believe that during the 95 model year there was an internal change, and synchromesh was dropped. This might make the earlier TC a bit easier to shift under adverse conditions, or if you have a disconnect front axle that is lazy in engagement.

I think what I will do in that case is hold onto the old t case, tail, and tranny adapter. If it becomes an issue I will do something about it. The only thing I owe the yard I bough the tranny from is the tranny, not both. Not sure why... but whatever. Also, I have a non-disconnect front axle, would the 95 syncromesh drop affect me in such a way to merit changing t cases?

if you think the driveline is to long cycle the suspension.

i think the only time the drive line being to long would matter is if it didnt fit at all or if the suspension was fully compressed and the drive line slip yoke pushed against the t-case which would be bad.

I also have been tossing around the idea of lifting the jeep to remedy the problem

xeroOTG said:

I think what I will do in that case is hold onto the old t case, tail, and tranny adapter. If it becomes an issue I will do something about it. The only thing I owe the yard I bough the tranny from is the tranny, not both. Not sure why... but whatever. Also, I have a non-disconnect front axle, would the 95 syncromesh drop affect me in such a way to merit changing t cases?

Click to expand...

If you have no disconnect, don't worry about the later T-case. I have felt no difference at all between the two versions over the years. I don't even know which type my 95 had, and would have been entirely unaware of it if I didn't have the 95 service manual. I think the only time you might find a difference would be if you're trying to shift into 4WD after you've started to lose traction. Otherwise, I think the later version may shift out of 4WD a bit more quickly when the driveline is binding a bit. The old 87 could stick for a long time before it popped, but the 99 seems to come out no matter what.

A few issues -
You can't swap the old tailhousing and old driveshaft with the new transfer case. The rear output shaft on the newer case is different from the old one, different length, different bearing positions IIRC, seal is in a different spot, etc. But you can swap the whole old case onto your new trans no problem I believe - it's definitely the same spline count, I'm just not sure if the input gear length is the same. I believe it is.

Your new transmission has a different input and output speed sensor setup from the old one. It has an input and an output of the hall effect type while the old one had only an output sensor of the reed switch type. For the output sensor you can simply swap the tail housing, sensor switch, and rotor off the old transmission onto the new one and splice the wires and it'll work great.

Front driveshaft is the same length between 97- and 98+ AW4s and also across all years of NP231s and NP242s so you are fine with your old front driveshaft.