Ryanc

What I am trying to state is how the hell could someone possibly know that the u joint caused that. Once that thing broke off the case at that velocity anything could have been deemed the cause. I am not saying a u joint cant cause this, just in this situation, how the hell would you know for sure. I would encourage folks to take their driveshaft they have and have a good ds shop available for installation and adjustment in angles, they have the tools to do this. One thing that has not been mentioned here, or anywhere on this forum is that as the JKs velocity increased the front pinion angle changes. Driveshaft shops know this and can adjust. This angle can change by 1-2 degrees. I am willing to bet this has an effect on this issue also. You could be sitting pretty at 0.5 degrees at 20mph, but go to 80 and you angle is 2.5 and then kaboom. This was not mentioned in the ds writeup on this forum and should have. The rzeppa can adjust and maintain "constant velocity". I ask again, how many rzeppa joints have exploded. NONE. Coast, Reel etc are great driveshafts. Just like gears, have a professional install them.

toymaster

I assure you a qualified person can look at the metal fatigue and damaged areas to tell what part failed first. Once again I, nor you, can tell from just photos. You said "no freakin' way"; I said yes it is possible.

Now on to having a "professional" install DS. Once again I assure you there is no magic involved to minimizing angle at a U-joint. While driving down the road the angle between transfer case and diff is always changing as the suspension is cycled. On flat ground and curb weight the pinion/DS angle needs to be zero because this is dead center for the suspension cycle. The front is a compromise between this and steering linkage geometry. If you are just referring to the joint at the T-case then it is what it is, period. They only way to change that is to change the trans or motor mounts. (as was common on TJs to help on the short rear DS)

The factory style joints are better EXCEPT for being able to take the increased angles of a lifted jeep. In the case the pros of an old school DS make up for the cons. The joints work great in their range of motion i.e. factory front wheel drive car or factory (low a$$) jeep.

If a person feels better if a profession does it then great, people do it everyday with oil changes. But there ain't no mystery to it.

Ryanc

Negative. Take someone who replaces their ds like the op and their trans blows up. Say they only drove 5000 miles. Take the stock one, 5000miles, not going to blow up. If you hypothetically replace the stocker every 1000 miles, your transfer case will not blow up.

Ryanc

It that mentality that is causing tf case failures.

Ryanc

Take nothing but highway usage 0-85mph. One is going to blow up if not installed correctly, the other will not blow up the transfer case. The stockers may in inself grenade itself, but it will not blow up the transfer case. Disregard any offroading. Im not saying double carden is bad, it is bad if you do not install it correctly.

Ryanc

There are actually some folks running their driveshafts.

wayoflife

if you are refering to the front shaft, yes. you can buy one and you will not need to get adjustable arms. if you are referring to the rear shaft, you WILL need adjustable rear upper arms as setting your pinion is required.

what nthinuf said

if you aren't having any problems with it, i would leave well enough alone. when it's time to get a new shaft, i would recommend getting an aftermarket shaft.

as i'm pretty sure i had mentioned earlier, yokes allow for better operating angles and this helps prevent vibrations. i never said that you would get vibrations with flanges but, the odds of you having them would be greater.

wayoflife

of course, you talk like you know what you are talking about and yet, you have never personally seen one of these things seize up and blow a t-case. i have personally seen two.

you don't know how the hell it could cause this because you have never talked to someone as it was in the process of seizing up and you have never seen one in person after the fact. honestly, i don't know why you are wanting to fight this one so hard but really, if you don't want to trust my experience in this matter, i would encourage you to get some first hand experience of your own. certainly, it would help you to make a better case then just adamantly believing whatever it is you want to believe.

easy - when you look at the centering ball of the double cardin, you can easily see and feel that it has seized up. most of the times, it will even have a welded look to it from all the heat it saw. the spinning force of your drive shaft has to go somewhere and if the joints aren't moving smoothly, something will break - in this case, it'll be the weakest link and that will be your t-case housing.

ummm, you can be willing to bet this but, you would be wrong yet again. this is definitly true of the rear drive shaft but only because of the torque the axle sees when accelerating.

if i recall correctly, i believe the OP did have a professional install his shafts about 3 years ago. i don't know how many miles he put on it since that time but even the best professional installer cannot ensure the owner of the vehicle will maintain the parts as is required. regarding rzeppa joints, what i can tell you is that i have personally seen MANY that have had compromised cv boots and still more with bearing that were going bad. in every case, the OP did what was needed and installed a new aftermarket u-joint style double cardin shaft to fix the problem. had they kept running the rzeppa joint till it failed, i can only guess what would have happen.

well, that's news to me. still, it doesn't change the fact that on a 4" lifted jk, the cv boot will be in a constant state of pinch and that will cause it to fail prematurely. of course, there is no way to maintain an rzeppa joint and i'd really like to see how much it costs to replace a bad one. being that you don't seem to care about any of this trivial stuff, i would encourage you to buy one

captjay

Thanks WOL, yes you did explain that and I understand the concept of the yoke and how you get better angles but what I'm not understanding is why would they have me install a yoke up front and the adapter flange on the rear? To me it would make sense to have installed yokes on both but because of the way the rear ds is designed, I don't think I can use a yoke on the rear.

mkjeep

I think RE designed them that way for ease of installation by kit installers. And yes you can use yokes all around, I do. Your ds would have to be re-built though(ends re-done.). Unless u can get a yoke match up. Seems like you could take off the flanges and do a yolk match up. But your ds may be too short then possibly.