T-case compatibility

Posted this on another forum, didn't get much action so I'll post it here.

Currently:
88 MJ SWB Pioneer
4.0 L
BA-10/5
NP 231 (21 spline)
D30 D44 w/3.07 gears.

Want:
(I have these parts)
96 NP249 (23 spline)
92 AW4 (23 spline)

Other than the gearing (for now) I want to swap the Peugot for the AW4 and put the NP249 behind it. Am I barkin' up the wrong tree here? Will this work? Any advantages, disadvantages?? I know I will have to swap some electricals but it seems that I have 2 plugs for the TPS, one looks just like my XJ with AW4. That plug is not plugged in. The other is in the TB.

Ideas??

Why on earth would you want a NP249 ????

I would NOT put a 249 in. I'd see if you can find someone who will trade for a 91-96 231 or 242.

The 96 and later cases will have the new style slip yoke and this may change your driveshaft length. Of course you're doing a BA5/10 to AW4 swap so you are changing length anyways, but the late model slip yoke design isn't as good anyways - unless you are doing an SYE then it doesn't matter.

You will need electronics (TCU, etc) for this swap unless you want to put in a custom shifter, which isn't that hard. The AW4 is easy to control electronically.

RCP Phx said:

Why on earth would you want a NP249 ????

Click to expand...

kastein said:

I would NOT put a 249 in. I'd see if you can find someone who will trade for a 91-96 231 or 242.

Click to expand...

Bingo, that's what I wanted to find out...I got this 249 for free...it's from a 96 GC. Not knowing much about TC's (year, troubles, strength etc.) I thought I might be able to slide it in when I do the swap with the AW4. apparently not a good idea.

My next question: Does anyone know if I can use the input (which is 23 spline, like the AW4) from the 249 into the 231 I have, or is it a whole different animal??

Should I just go get the 91-96 T-Case.

I'm a cheap barsturd and I'd hate to pay for something that I could use for free.

The 249 has a Viscous center differential(coupler),it is Full-Time only and doesn't have a way to "lock" the coupler.

I'm pretty sure you can't. Checking the parts catalog though.

231 input gear is 5300 6083, 5300 6084, 5300 6085, 8350 6065, 4761 068, 4796 904, 4796 905, 4796 956, 4796 965, or 4798 113 depending on what case you get out of a 94-96 :wow:

I don't think NVG was quite insane enough when they decided how the parts for these cases would be selected. Some of those are 23 and some are 27 tooth gears (teeth, not splines.)

249 input gear is 4761 192, 4728 163, 4796 972, 4796 976, or 4798 126, again depending on a million factors.

Since there is 0 crossover between those two sets of part numbers, I feel fairly safe in guessing you can't swap the gears.

Also, you want 91-95 not 91-96 - the 96 cases and later had the newer slip yoke design. 96 is one of those funny years where a lot of stuff is unique and many year splits don't line up.

Maybe you can find some guy with a ZJ who bought a 91-95 231 for a swap and would be interested in a 96 249?

RCP Phx said:

The 249 has a Viscous center differential(coupler),it is Full-Time only and doesn't have a way to "lock" the coupler.

Click to expand...

:confused1 No comprende!
I just need to know if it'll work, and apparently it won't. The 231 has never let me down. I thought a newer year, less mileage, might be an upgrade. No!?
...and just for my own info, why is Full time bad? Is it always on full time or just when the t-case is engaged??

kastein said:

Maybe you can find some guy with a ZJ who bought a 91-95 231 for a swap and would be interested in a 96 249?

Click to expand...

Holy Cow!! I guess that'll be what I'll be doing. Although I haven't had any trouble scoring t-cases. I have 4. Bait and switch time.:shhh:

Oooh!! One more question...could I just get a new input for my 231??? ..or is that more trouble than it's worth?

Its not a bad job to switch input gears in a 231J. PartsMike is a good source; helpful and very fair prices.