The cases that I've seen fail have all been rubicon cases, that said I believe that the case half's for the 3.21 and the 4:1 are the same. It is just the internal gearing that is different.

There has been a lot of debate about a different DS design that doesn't use the double Cardon joint. Most on the forum believe the double Cardon is the better joint. To be honest I really don't know the technology about the difference between the 2 joints. I know of no TC failures with the new DS design, but then again I don't know of anyone who is actually running with it. I have also not heard of anyone running it for a long enough time to profess that it's better and that it will solve TC failures.

 

Thanks foe the info on where to look for cracks in the t-case.

 

the only bad news here is hearing guys like you come on this forum with terrible and uneductated information like this and as if you were actually some kind of authority on the matter

aftermarket drive shafts ARE NOT what are causing the problem - vibrations are and most of these are caused by too much caster on a jeep that's running 5.13 gears or higher. fancy joints or less massive drive shafts are NOT what is needed to address vibrations - making sure that you have the proper caster set and that your drive shaft is well balanced is.

 

Yes, I agree, vibrations are causing this. So you can tell all of us that the combination of low gearing with an aftermarket driveshaft, and bad driveline angle is not causing this? So lets play a little deductive reasoning game here. There are many more folks running lifts with aweful castor specs and are geared low running a stock driveshaft than those running this same set up with an aftermarket ds. Not ONE has blown up a t case with a stock shaft on.

 

LOL!! speaking of terrible and uneductated information and as if you were actually some kind of authority on the matter, i should have known that the boy genius who "says" he helped assist in the development of the thompson coupling would chime in on this thread. perhaps you can help enlighten and educate us again with your vast wealth of knowledge on this matter. or, maybe it would be better if i just provided a link to our last conversation on this

https://www.jk-forum.com/forums/show...-case-exploded

LOL!! in spite of what you seem to think, just because you haven't read about it on the internet doesn't mean that ONE hasn't blown up a t-case. also, an rzeppa joint makes all kinds of really bad noise when it's going bad and lets you know in a real hurry that something is wrong. most people are forced to address the problem right away like this guy:

https://www.jk-forum.com/forums/show...-popping-sound

make no mistake, once the joint seizes up, bad things would happen. of course, if you spent less time reading things on the internet and more time working on jeeps and or wheeling them, you would know this.

 

"Too much caster" and "bad driveline angle" are about the same thing in this situation.
The two of you have said the same thing, using different points of reference.

 

LOL!! just to be fair, he's saying the same thing as me - just using a different point of reference. still, too much caster or, as he liked to put it, a "bad driveline angle" is a problem with install error and NOT a problem with the type of drive shaft used.

 

That is true.