Did Jeep ever use the New Process 231 tcase?

[bitofaclue]

I'm actually looking for one for a '91 Dakota - should I be asking here?

thx.
jl

[apeman]

Kinda rare. They only got used in about 10 million yj, tj,xj and zj's.

[bitofaclue]

Yeah, that sounds rough alright.  Anyone have one to spare?

[vantagetes]

Several issues here. You'll need to find one with the vacuum tube to control your front axle disconnect, (91 or older) and after 91 they have electric speedo hookups vs your cable. There are also two different spline counts (23 and 21 spline) and they aren't as rugged. The NP231D has a wider chain and gears then the NP231J.

Not sure about the difference in clocking. They should all bolt up (as well as the cherokee NP242J) it's just a question of maybe banging up your transmission tunnel a tad and monkeying around with shifter linkage to get the correct length.

[BlackYJ]

Not sure about the difference in clocking. They should all bolt up (as well as the cherokee NP242J) it's just a question of maybe banging up your transmission tunnel a tad and monkeying around with shifter linkage to get the correct length.

The clocking comes from the transmission and not from the t-case.  The XJ t-cases hang lower than YJs

[JENSSEN]

Think I have a vacume one kicking around

[bitofaclue]

Several issues here. You'll need to find one with the vacuum tube to control your front axle disconnect, (91 or older) and after 91 they have electric speedo hookups vs your cable. There are also two different spline counts (23 and 21 spline) and they aren't as rugged. The NP231D has a wider chain and gears then the NP231J.

Wow - this is the kind of detail I need.  Thanks for wading in.

What I have is a 231D, and I assume the spline count you're referring to is the input (transmission) shaft.  If so, mine is 23.  The output (driveshaft) is 26 splines, if it matters/differs.

There's a little adapter on the speedo output that has a wiring connector in addition to the speedo cable - I assume that's for the cruise control.

Not sure about the difference in clocking. They should all bolt up (as well as the cherokee NP242J) it's just a question of maybe banging up your transmission tunnel a tad and monkeying around with shifter linkage to get the correct length.

What do you mean by "clocking"?  I don't think I've heard the term before.

[bitofaclue]

Think I have a vacume one kicking around

I just dropped you an email.  I'd really appreciate your checking and seeing if you have one available.

thx.mch.

Jonathan

[cLAY]

Clocking refers to what angle the t-case bolts onto the tranny. The bolt pattern is rotated differently on some vehicles so that the t-case hangs down lower. Shouldn't be an issue for you since the tranny sets the indexing, the t-case patterns are the same.

You can also use a non-disconnect vacuum t-case by just plugging the lines and then removing the vacuum shift motor in the front diff and shimming the fork over so it just stays in the locked position permanently.

[bitofaclue]

Clocking refers to what angle the t-case bolts onto the tranny. The bolt pattern is rotated differently on some vehicles so that the t-case hangs down lower. Shouldn't be an issue for you since the tranny sets the indexing, the t-case patterns are the same.

Ah, okay, I get it.

You can also use a non-disconnect vacuum t-case by just plugging the lines and then removing the vacuum shift motor in the front diff and shimming the fork over so it just stays in the locked position permanently.

Is there any downside to doing this?

[cLAY]

Front axle gears and front driveshaft will spin all the time. Sounds worse than it is. Most Jeeps(since mid 90s) and 4x4 trucks made today do not use a disconnect system and have no issues.

Most older Jeeps that have the system are starting to break down. Failed switches, vacuum leaks, moisture in the shift motor that freezes in winter are common problems that prevent 4wd engagment. After having all the above issues on my '89 XJ  I just locked the front diff in all the time and was much happier.

[Sean778]

I think the guys at Broken Axle had a used t-case from a Durango kicking around at one point.  I don't know if it would work or not, but it would be worth looking into for sure.

[BrokenAxle]

Yes, we have a 231HD from a durango here.  It doesn't have any of the vacuum stuff on it.  Shoot me a pm or call me at the shop if you are interested!

Thanks
Dave
403-237-7706

[hps4evr]

Front axle gears and front driveshaft will spin all the time. Sounds worse than it is. Most Jeeps(since mid 90s) and 4x4 trucks made today do not use a disconnect system and have no issues.

Most older Jeeps that have the system are starting to break down. Failed switches, vacuum leaks, moisture in the shift motor that freezes in winter are common problems that prevent 4wd engagment. After having all the above issues on my '89 XJ  I just locked the front diff in all the time and was much happier.

Sadly last I read dodge will be going back to a disconnect type front axle on 2500-3500. Not sure if it's vacuum actuated or what, but looks similar to the old designs... I guess anything to gain a little efficiency...

[cLAY]

I wouldn't mind having it back actually.  2wd low when backing up a trailer is pretty sweet. I'd like to see locking hubs back like the Superdutys. Leave it in if you want, unlock it when you want.