231 to 242

im starting to plan out a 231 to 242 transfer case swap. i currently have a 1988 4.0 with aw4 and have not found one for that year range. what would be the best option to get a newer one to fit? or can you just order a new input shaft to fit the 21 spline transmission

im planning on next summer if i can get this all figured out.

IIRC, input shaft for both cases is the same. So, an option is to pull both apart and rebuild the 242 with the 21-spline input.

1987-1993 242's should bolt right in.

Novak Adapters advises "Because of differences in the cut of the internal gears, as a general rule, one should not interchange 1987-1993 gears with 1994-present gears." As I understand this you won't be able to use 1994 and newer 242's by just swapping the input shaft.

Difference will be the input shaft spline count which is unique to renix jeeps and is 21 spline. I have one for sale but I'm on the wrong coast to be of much help. But yes you can take them apart and swap the input gears I believe

that would save a lot of head ache. next is figuring out wiring. and if its possible to keep the axle disconnect.

90xj06 said:

that would save a lot of head ache. next is figuring out wiring. and if its possible to keep the axle disconnect.

Click to expand...

A 21 spline case from an 87 to 90 will bolt right in.

You can install the shifter and bezel to make it like factory.

You want to get rid of the axle disconnect, not keep it. Here's how, and why:

http://www.cherokeeforum.com/f51/free-d30-cad-bypass-91-a-38629/

CAD STINKS


The big issue is that the CAD system only fails when you need it the most.

Kinda like when you don't realize your wiper blades need replacing until it rains....

I know somebody’s system works and he advocates keeping it stock, but my exposure to the failures is probably hundreds of times greater than his, as a result of being Service Manager at a Jeep dealership from 1980 through 1992, and being a current XJ and MJ owner.

CAD stinks. Every Jeep I work on with it, I eliminate it. Guess what I find in the process? 25 year old busted vacuum lines, bloated vacuum line connectors, bad vacuum reservoirs and piping, bad transfer case vacuum switches. In other words, had the person gotten into a sticky situation and needed 4WD, they would have been screwed!!!

That's the tip of the iceberg. The factory went through 3 revisions of the shift fork also. The fork issue is non-existent if you just slide it over and leave it.

See the link below for complete instructions. Takes less than 1/2 hour.

http://www.cherokeeforum.com/f51/fre...ss-91-a-38629/
,

i sort of used that fix on my other jeep. but i just slid the lock ring over and put the fork on the other side. if i was to swap it out with a mechanical cable that would that also be a fix too?

90xj06 said:

i sort of used that fix on my other jeep. but i just slid the lock ring over and put the fork on the other side. if i was to swap it out with a mechanical cable that would that also be a fix too?

Click to expand...

Don't bother with a cable. 242s had no disconnect anyway. No advantage to keeping that crap.

i figured i could squeeze a few more mpgs while it was in 2wd. unless this is moot

cruiser54 said:

Don't bother with a cable. 242s had no disconnect anyway. No advantage to keeping that crap.

Click to expand...

I have to completely disagree with that statement, though I value your opinion. I run my CAD 30 with the mechanical cable and love it.

• I run 2L a lot and don't need a twin stick or have to shell out $1200 for locking hubs.
• I don't need to keep my front ds balanced because it only spins when I'm wheeling or in snow on the roads.
• I don't need to turn my c's. I refuse to jump on the bandwagon of saying pinion takes precedence over caster. Good pinion is convenience, good caster is safety so when/if I ever go with a front axle that requires the front DS to spin all the time, I will balance it and turn the c's to get the best caster and pinion angles.
• Though I don't do this, I hear it makes it easier to spool or run an auto locker up front since you can just disconnect the axle from the cab instead of getting out and unlocking hubs. I wouldn't personally run a spool on the 30 but this makes it easier

Given all that, if I had a chance to upgrade to a better axle with a selectable locker, I absolutely would, but given that there is a CAD there, I'd say use it with a mech cable vs. the vacuum stuff. Get the shorter cable and don't let it touch the exhaust.

90xj06 said:

i figured i could squeeze a few more mpgs while it was in 2wd. unless this is moot

Click to expand...

I haven't noticed a difference connected vs disconnected, but my gas mileage sucks already. I can't handle the vibes for more than a tank so I also didn't measure the best way possible either.

ill have to think about this one.

also does both the part time and full time light work on the 242? and would a harness from a 91+ work in an 88? also is the wiring there for the full time light?

The plug is no different IIRC. You'll just need a bulB in the dash. And you can keep your CAD vacuum operated anyway since the 242 does not have the provisions for the vacuum stuff on it. No 242 came with a CAD front axle

90xj06 said:

i figured i could squeeze a few more mpgs while it was in 2wd. unless this is moot

Click to expand...

Moot.

The 242 doesn't have a vacuum switch (factory D30 with 242 didn't have the disconnect either), so vacuum CAD isn't an easy option anyway. Its doable with some engineering, but much simpler to eliminate it or use the cable.

As for the input shaft, other people already said to watch for the internal gear changes. Three factors are external spline count and shaft length (spline depth), and internal gear cut. If you want to reuse your existing input shaft you will need a 242 from 93 down to match all three. One thing I have heard of but never seen or done first-hand, is using an input shaft from a jeep with a 94/95 AX-5 (also 21-spline, with the newer gear-cut, but longer) and then cut it down to the proper length.

There are not any huge advantages to the later style. In fact the older ones are better because the Full-Time differential has six bolts instead of three, so it deforms less under extreme torque. Not worth the trouble you have to go through.

I saw a 92 242 at the yard already pulled. If it's still there I'll grab it. And I'll try and grab the harness

One other thing in case it wasn't clear, Full-Time will not work with the CAD in disconnected position.

ehall said:

One other thing in case it wasn't clear, Full-Time will not work with the CAD in disconnected position.

Click to expand...

That's what I was thinking.

ill do the lock ring hootenanny

picked up a 242 from a 92 for $110 is there any writeup on how to change the input shaft? i should probably check the transmission too as the engine was swapped out with a ~93 maybe it has the same year transmission. doubt it but you never know.