Well the deal all started about 2 weeks ago. I was driving and heard a fairly faint banging comin from under my jeep. I put it on a lift at work and the other guy got under it and says the banging was coming from the transfer case so i took my front drive shaft out for the time being and it stopped. Well i priced out a 231 from a buddy that works at a junk yard and i picked it up for 50 bucks (109000 miles on it). I then decided to buy the rebuild kit for it and basically make it new again (Novak see here). So anyways we're all good then my dumbass realized i have a 242 (PT FT). So my question is (see my profile for jeep build, 01 XJ, 4.5 RC lift, daily driver) can i just rebuild the 231 and put it in replacing the 242 or what. I mean is it gonna have negative effects on the drive line and will it bolt straight up? Help!

 

Sounds like cv in the front driveshaft is worn out. Nothing to do with the t-case. That's why it stopped when you pulled the shaft. Happened to my rear shaft.

 

I thought about that... do you think the sound would travel through the t-case too giving the illusion that it's bad?

 

Sure, that's possible, the cv is right up near the t-case. Inspect the driveshaft since it's out, see if the cv is loose or binding.

 

Well how about this? When i pick the driveshaft up off the bench the CV will basically free-fall forward and backwards (too loose??) but it barely moves left and right (too tight??). Also where the CV falls it just-so-slightly hits the U-joint. Is that normal?

 

free falling is fine. if it is worn and it binds, pretty good chance the needle bearings in the u-joints are nothing more than rusty powder...

 

if i understand that correctly sounds like the bearings are are toast in the joint, mine had similar symptoms and when i pulled it apart the bearings in 2 of the ears had turned to dust.

all that said if you wanted to put that 231 in it is possible, the difficulty of the switch however depends on the trans output which i believe by 01 were all 23 spline but dont hold me to that number, double check for yourself....or just stick with the 242, its a nice case.

 

Well that's my whole thing tho, i can't tell if it is worn and binding or if the movement left to right is more limited because of the way it fits up to the driveshaft.

 

you should have free movement regardless. smooth to the limit of it hitting. when it is attached, it wont hit those limits (unless your DS angles are WAAYYY off)

 

Well at this point i'm going to say it's probably not the CV. Talking to my other guy here he says it sounds like the chain is smacking in the bottom of the t-case. So back to my original 242 to 231 swap, thoughts?

 

chain slap would sound like a tick, not a bang. im betting on double cardan joint on the front driveshaft.

 

X2 on that

as for the swap i covered the points in my previous post

-check the spline count on the trans output shaft to determine whether or not you would need to swap inputs on the case

if you did go ahead with the swap you would need to replace
-shifter bezel
-shifter assembly
-shift linkage

possibly drive shafts but not 100% on that one

 

could be the t case, remove the rear driveshaft put the trans in N and spin the front driveshaft while its in 4x4, if there is alot of slack between the front and the rear out put(witch there will be if the chain is stretched. i just did a transcase swap its very easy). mine was making some bad noises! just check for slack everywhere.

 

It might not be the joints itself in the cv but the ball and socket in the center. That's where mine went bad and it was making the same exact noise. You pulled the driveshaft and it stopped. Usually that would pinpoint the problem. Put the t-case in 4hi so the front output is turning, and take it for a ride. Leaving the front d-shaft out. If it still doesn't make noise, I guarantee it's the shaft.