Premature u-joint wear

Does the jeep get much use in mud or water? A lot of winter rainy weather? The lower joint at less angle failing first makes me think water comes into play. Or like blackjack says,maybe deformity in the yoke or straps is distorting the caps?

If you strap down just the rear joint and swing the driveshaft around does it move freely in all directions?

No binding?

For what its worth i have a similar amount of lift and went with an sye and double cardan shaft to eliminate vibes. Its been holding up well for a couple years behind a healthy stroker
 
You really need to figure out why your tcase output shaft and pinion shaft angles are so different...

OP, you currently have OEM upper control arms and lift-kit lower control arms, right? What are those lower control arms like? What length are they, bolt-to-bolt?
 
OP, you currently have OEM upper control arms and lift-kit lower control arms, right? What are those lower control arms like? What length are they, bolt-to-bolt?

15.75” which I believe is stock length

image.jpg
 
Close but slightly different — unless you or I mis-measured. My OEM LCAs are 15-7/8". I wonder why your lift kit included them.

Those look like a rip-off-your-brackets type of a design. If you flex your suspension much on the trails, the semi-flexible OEM ones or adjustable ones with a swivel-type joint might save you a lot of grief.
 
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Does the jeep get much use in mud or water? A lot of winter rainy weather? The lower joint at less angle failing first makes me think water comes into play. Or like blackjack says,maybe deformity in the yoke or straps is distorting the caps?

If you strap down just the rear joint and swing the driveshaft around does it move freely in all directions?

No binding?

For what its worth i have a similar amount of lift and went with an sye and double cardan shaft to eliminate vibes. Its been holding up well for a couple years behind a healthy stroker

It’s my toy now so I don’t drive it every day. More of a thing I’m using to learn about cars. I’ve had it since 2002. I’m from Wyoming so it used to get plenty of time in snow. Mostly pavement with some occasional Forrest service roads these days (last 15 years)

Driveshaft moves freely
 
Close but slightly different — unless you or I mis-measured. My OEM LCAs are 15-7/8". I wonder why your lift kit included them.

Those look like a rip-off-your-brackets type of a design. If you flex your suspension much on the trails, the semi-flexible OEM ones or adjustable ones with a swivel-type joint might save you a lot of grief.

Would it make any sense to go longer than stock? I’ve read you can start to interfere with the track bar if yo go too far back.
 
I doubt if you can find any fixed-length CAs which are a specific length you want. And if you did, and you had an interference problem, how would you fix it?

No, it's pretty much stock or adjustables.
 
I doubt if you can find any fixed-length CAs which are a specific length you want. And if you did, and you had an interference problem, how would you fix it?

No, it's pretty much stock or adjustables.

I would definitely go with adjustables but not sure how much room I have to play with and what effect longer lowers would have on the angles.

I’m visualizing bringing the axle back would also lessen that upper working angle. Think I would still have to adjust the pinion down but perhaps I’d be good to go with the longer hypotenuse. Might go down the trigonometry rabbit hole now.
 
Here’s a pick of the yoke:
There is some play left to right with the Ujoint in the yoke.

View attachment 476801

There should be no play with an SPL joint even before you put on the straps. It would appear that a cap may have spun in the yoke at some point in time. I would replace it and make sure to use new straps and bolts.
 
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I would definitely go with adjustables but not sure how much room I have to play with and what effect longer lowers would have on the angles.

I’m visualizing bringing the axle back would also lessen that upper working angle. Think I would still have to adjust the pinion down but perhaps I’d be good to go with the longer hypotenuse. Might go down the trigonometry rabbit hole now.
You're over thinking this, you keep thinking you need to learn trigonometry to fix this.
 
From your angle measurements you just need to lower the rear pinion angle by 4.9 degrees to match the tcase output shaft angle. You can shorten the upper arm length to do that which will move the axle slightly forward. Or shorten the upper arm and slightly lengthen the lower arm to leave the axle where it is. Your choice.
 
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Thanks everyone for your tips and ideas. I’m going to try the transfer case drop, replace the rear yoke and put a cap on this thread for now. I’ll post the angles after the drop for informational purposes. Thanks again!
 
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Dropping the tcase might just help. Even so that's seldom needed for a 1.5" lift so it's all still a bit of a mystery how those angles and vibrations came to be.