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Discussion Starter · #1 ·
Hello everyone. I’m getting front driveline vibes in my TJ dana 30 with 4” suspension lift. The ujoint nearest the diff moves side to side in the driveshaft yoke. It looks like bearing cap lateral movement. I’m wondering if I should just have the driveshaft rebuilt and if the yoke is damaged Can the gap be lessened between the ears for a tight fit? Or would I be ahead to just replace the whole shaft and be done with it? I was quoted $160 for the rebuild with spicer 5-1310 non grease level joints. A new driveshaft would be around $290+ from Adams driveshaft which I have their rear.

Also the front pinion angle is 7° and the driveshaft angle is 8.5° is that difference alone enough to cause the vibes? I have stock upper control arms. I’m also running with the front drive shaft removed until I remedy this problem.
 

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To start with, just replace the bad u joint...
It's not that hard to diy
 

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Just went through this on my Jeep. Gonna need to replace the ujoint and probably the yoke as well if the little tabs on each side of the yoke are worn.
 

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The vibe maker and U joint killer is having 2 differing angles at either end. This causes the U joint to turn 2 different speeds at the at either end.. Sounds weird, but for one Woods drive lines has a very informative bunch of information on the subject. Im im understanding you the U joint cap are moving in the yoke? If that's the case then the U joint straps are loose, worn or the yoke is worn out. Caps tight but the joint cross section moves back and forth in the caps, then the U joint is just worn out. Easy fix, do both ends and frankly trying to get the angles 100% correct on the front may not be tough as that would require turning the axle tube which affects alignment Caster. Unless your running at speed on snowy highways in 4x4 hi for miles on end you should get year of service outta just replacing the U joints with quality Dana/Spicer ones. You should be able to get serviceable ones a well, but that's up to you.
 

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Discussion Starter · #5 ·
The u joint caps are actually moving in the yoke on driveshaft itself. I just had my front pinion yoke and pinion seal replaced and went with a u bolt style yoke. But the joint is actually moving back and forth in the driveshaft mount not the pinion yoke.
 

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Please climb under there and look if the straps are loose or? I say this because of the potential nightmare of safety issues possible if for some reason the front of the driveshaft drops and hits the ground. If this happens and it gets hung up in a rut or crack in the pavement while moving it could cause massive damage to the transfer case and worst yet, you and any passengers. If the straps are snugged up I cant see how they could move in the yoke. Also there should be tabs or a ridge on either side of the yoke that keeps the U joint centered in the yoke or sliding side to side. The U bolt style straps are nice,however if not careful you can actually deform the U joint ends overtightening them which will damage the U joint. Sounds like the shop didn't do the job correctly.
 

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Discussion Starter · #7 ·
The straps were not loose, the driveshaft is now removed so no safety concern. The shop did excellent work On the regear, and this issue had nothing to do with the shop it was there prior to the work. THE MOVEMENT IS NOT ON THE CAPS THAT STRAP TO THE PINION. It’s on the driveshaft with the bearing cap pressed into the shaft held on with the retention clips. Not the end that straps to the pinion yoke. Maybe I’m not explaining this very well.
 

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The vibe maker and U joint killer is having 2 differing angles at either end. This causes the U joint to turn 2 different speeds at the at either end..
That makes sense for a single cardan shaft like the stock rear. The front has a double cardan joint so the ideal pinion angle is straight with the driveshaft, just like a DC rear with SYE.
 

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The straps were not loose, the driveshaft is now removed so no safety concern. The shop did excellent work On the regear, and this issue had nothing to do with the shop it was there prior to the work. THE MOVEMENT IS NOT ON THE CAPS THAT STRAP TO THE PINION. It’️s on the driveshaft with the bearing cap pressed into the shaft held on with the retention clips. Not the end that straps to the pinion yoke. Maybe I’️m not explaining this very well.
You're explaining it well enough to me. 🤷‍♂️

I would just start with replacing that joint and see if a new one rides tightly in the yoke. If it does, send it. Otherwise you'll need a new shaft or someone to put a new yoke on yours.
 

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The straps were not loose, the driveshaft is now removed so no safety concern. The shop did excellent work On the regear, and this issue had nothing to do with the shop it was there prior to the work. THE MOVEMENT IS NOT ON THE CAPS THAT STRAP TO THE PINION. It’s on the driveshaft with the bearing cap pressed into the shaft held on with the retention clips. Not the end that straps to the pinion yoke. Maybe I’m not explaining this very well.
Gotcha, guess the brain didnt grasp that one as Ive never had them go loose on the pressed in side. Like the mentioned try a new joint and if that dosent correct it then a new DS looks to be in order.
 

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Sounds like a bad joint. Order all 3 and replace them while you have the shaft out. Also replace the centering ball on the double cardan while you’re at it.
 

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Discussion Starter · #12 ·
Alright, I got a new splined yoke on the driveshaft and a new ujoint on the front. The shop also balance the shaft and said it was slightly out of balance. I installed the shaft and it still vibrates, not as bad, but still vibrates. Anything above 55MPH. I removed the shaft just to confirm that it wasn’t the rear. How often does the CV end of the driveshaft go bad? It’s not squeaking and the PO said he replaced them and they still look new and shiny. Should I go ahead and replace the centering ball and 2 other ujoints? Should I consider replacing the H yoke as well?
 

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With the drive shaft uninstalled, move the double cardan end around. It should be nice and smooth with a bit of over-center spring action as it moves from one side to the other. A worn out centering yoke will also sound like a bunch of angry sparrows under your jeep :)

With the driveshaft installed, grab the input yoke on your front differential and give it a hard shake to see if there's any play in the pinion bearing. Do the same with the output yoke of the transfer case, just keep in mind that it will have a little axial play. If there's no play in any of the bearings, I would try to zero the pinion angle.
 

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If you adjust your front pinion angle, keep an eye on the caster angle. Caster angle can be a bit less (numerically) with larger tires, but should be somewhere between 4 and 7 degrees. Try to get within 1 degree on the pinion angle, then if you don't notice increased wandering in the steering when driving, you should be good.
 
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