Swapping a 242 t-case for a 231

Hello, all


I have a stock 1988 Wagoneer(XJ). I love the thing to death, the only problem is that the transfer case was cracked. I had it welded up, but it still has a slow leak around the cover gasket. Unfortunately, the cover was welded to the rest of the case in the repair process, making it impossible to fix.
My question to all of you guys is this: Can I swap out my 242 t-case with a 231? I already have a 231 in my shed. I bought it from a junkyard in Ohio, they shipped me the 231 instead of the 242. Instead of shipping me another one, they refunded my money.
If the swap is possible, can it be done relatively inexpensively?
I understand that I will lose the ability for 4-full time, but, since my last 85 XJ didn't have that option, it's not a big deal.


Seth

IF the cases share the same spline count (21 sp in this case) it is a easy swap. I replaced my 242 for a 231 in my 89 last winter.

IIRC I used the link rod from the 231, and since my ex-242 Jeep had the non-disco axle, i just capped off the vacuum ports on the 231 vac-switch. The 242 has an elec. plug that lights the dash lights...I left this part undone - I know when I am in 4x4 low, and I rarely use 4 high. (The 231 doesn't need vacuum input...it's just for the lights and the axle disco motor)

Other than the dashlight switch & capping vacuum...it's a great time to add a fresh vent hose/check valve & run it up to higher ground.

I swapped the bezel on the console to show the 231 modes.

HTH & have fun...I think it took me a couple hours tops, working on my back in the cold gravel. It is WAY easier to hook up the vent hose when the case is loose, trust me!

When the Jeep was at the mechanics, he had taken the 242 out to compare it with the 231, and the spline count was both 21. However, it appeared that the 231 had a bit longer case....

Forgive me for this, but some of your references are confusing to me. I am really new to the world of Jeep repair, and I want to learn as much as I can...
Link rod? Non-disco axle? Vent hose, check valve???
My mech mentioned something about the ratios, and it might bind up. Is that the case here? What about driveshaft style and length?

Like you, I rarely use 4HI, so I don't care if don't have a light telling me so.
BTW, Am I correct in assuming that the t-case is completely mechanically operated? I remember on my old 85 Wagoneer, the front axle had this forked lever of some sort and the vacuum would move it into place, engaging the front axle.

Seth

Link rod= the rod that connects the tcase shifter to the tcase.

Non disco axle= your waggy had a disco. That fork disconnected one sides axleshaft. Since you have a 242 your front axle doesn't have a disconnect in it.

Vent hose= your axles, tranny, and tcase all have this. It's to allow these pieces to be able to vent off pressure so that they don't blow the seals as they get hot.

check valve= typically it's a little attachment that has a ball in it to allow fluid/ air to flow one way and not the other. I'm not too sure, but I don't think the tranny or tcase have these, they just run a regular old hose.

Your junk is only going to bind up if your front and rear axle have different gear ratios in them. I'm slightly worried about the competence of your mechanic now.

Driveshaft style is the same, although I do believe the length is different.

You're correct, the tcase is entirely mechanical.

what are the chances that they WONT have the same spline count on the input?? i may be doing a similar swap eventually....
pm'd ya DG..
mike

I too was (and still am) very worried about the competence of my mech. But since my Jeep broke down about 300 miles from my house, I didn't have much of an option.

If the style of the driveshafts are the same, but the lengths are different, does that mean that I have to modify my shafts, or get new ones?
If thats the case, then I would be better off just dumping in tranny fluid every couple of weeks.

Seth

My Waggy didnt have a Disco
1987

You can go to the junkyard and get the right shaft, or you can have your current one lengthened or shortened, whatever the case may be.

I went to the junkyard, and they only list one model for the driveshaft. Regardless of t-case model.....

Seth

Well then, in theory you should be good to go. Maybe you could ask on the oem tech board for measurements of stock shafts from u-joint to u-joint for the different tcases.

Thank you for all the help. As I'm sure you can see, this is all new to me.


Seth

My 231 came out of my 89 5 speed MJ and went into the Auto XJ, and used the (fresher) 5-spd MJ front shaft. It's a bit shorter than the auto front shaft, but the rear shaft is OEM 242/AW4 XJ and both DS work fine.

Like One Ton says, the bind comes into play when/if you had two dissimilar axle ratios (or grossly mismatched tire diameters) f & r

Sidriptide, stick with older cases for your older 21-spl Jeeps...IIRC around 90 or 91 they started shipping 23 Spl cases behind the AW4. From the factory, all AX15 are 23 spl and all Peugot BA10/5 were 21 spl.

thanks woody.. the 231 is from my other 87...