Driveline Vibration Question/Help

blackrubi14

blackrubi14

Member
2014 JKUR 3" lift, 37" Toyo's, 4.56 gears, JE Reel 1350 front driveshaft, stock rear driveshaft, adjustable front LCA's and adjustable track bar.

Installed front driveshaft back in February while still on 35's, no vibration at all. Went to 37's in in March, no vibration. Added adjustable front track bar, no vibration. We to Arkansas on a wheeling trip at the end April, drove to and from, no vibration. A few weeks ago I went to Disney to play around a little, did not do anything hard, didn't push the jeep at all. After that trip, I started to notice a slight vibration. Over the next few weeks it got a little more noticeable, not bad but noticeable. I installed adjustable lower control arms last week (previously had drop brackets, I know, stupid) hoping that would correct the vibration, it helped but did not fix the issue. I pulled the front driveshaft and no more vibration, the weight is still in tact and there are no visible signs that the shaft has been hit, and the u-joints appear to be in good shape, the shaft is only a few months old.

Is it possible the shaft is out of balance, u-joints already bad? I wouldn't think the shaft would just go out of balance without losing a weight, or being hit, but I guess it's possible tho.

Would the adjustable front track bar cause the yoke on the axle to not line up enough with the yoke on the t-case to cause a vibration?

Any ideas?
 
scull20

scull20

New member
blackrubi14 said:
2014 JKUR 3" lift, 37" Toyo's, 4.56 gears, JE Reel 1350 front driveshaft, stock rear driveshaft, adjustable front LCA's and adjustable track bar.

Installed front driveshaft back in February while still on 35's, no vibration at all. Went to 37's in in March, no vibration. Added adjustable front track bar, no vibration. We to Arkansas on a wheeling trip at the end April, drove to and from, no vibration. A few weeks ago I went to Disney to play around a little, did not do anything hard, didn't push the jeep at all. After that trip, I started to notice a slight vibration. Over the next few weeks it got a little more noticeable, not bad but noticeable. I installed adjustable lower control arms last week (previously had drop brackets, I know, stupid) hoping that would correct the vibration, it helped but did not fix the issue. I pulled the front driveshaft and no more vibration, the weight is still in tact and there are no visible signs that the shaft has been hit, and the u-joints appear to be in good shape, the shaft is only a few months old.

Is it possible the shaft is out of balance, u-joints already bad? I wouldn't think the shaft would just go out of balance without losing a weight, or being hit, but I guess it's possible tho.

Would the adjustable front track bar cause the yoke on the axle to not line up enough with the yoke on the t-case to cause a vibration?

Any ideas?
Click to expand...

What did you set the pinion angle at?
 
blackrubi14

blackrubi14

Member
scull20 said:
What did you set the pinion angle at?
Click to expand...

When I started I was measuring off the top of the ball joint, with a starting length of 23" eye to eye on my LCA's, I was getting a reading of 4-4 1/2. I started making the LCA's shorter and it helped the vibration, but did not cure it. I just measured off the flat circles on the front of the axle housing and it reads 89. This is reading with my iPhone.
 
scull20

scull20

New member
blackrubi14 said:
When I started I was measuring off the top of the ball joint, with a starting length of 23" eye to eye on my LCA's, I was getting a reading of 4-4 1/2. I started making the LCA's shorter and it helped the vibration, but did not cure it. I just measured off the flat circles on the front of the axle housing and it reads 89. This is reading with my iPhone.
Click to expand...

You may want to check it with an analogue angle finder that will stick to the axle housing with a magnet. Also, were you in flat ground?...assuming you followed the steps in Eddie's self alignment write up.

Is there any vibration translated into the steering wheel?...just to be sure the tires are balanced.

Otherwise, if the shaft is pulled...most local driveshaft shops are happy to balance it for you, if need be. Probably won't cost much.
 
blackrubi14

blackrubi14

Member
scull20 said:
You may want to check it with an analogue angle finder that will stick to the axle housing with a magnet. Also, were you in flat ground?...assuming you followed the steps in Eddie's self alignment write up.

Is there any vibration translated into the steering wheel?...just to be sure the tires are balanced.

Otherwise, if the shaft is pulled...most local driveshaft shops are happy to balance it for you, if need be. Probably won't cost much.
Click to expand...


I bought an angle finder today, the pinion angle showed 3 degrees. Yes, all measurements have been taken on flat ground.

No vibration in the wheel, I can mainly hear it and see it it my mirrors, no feeling in the t-case shifter or the transmission shifter.

I plan on taking the shaft to a local driveshaft shop to have them check the balance. The u-joints look and feel good.
 
scull20

scull20

New member
Also...someone else may be able to chime in on this one, but assuming you have an aftermarket DS, did you ensure you torqued the new yoke at the TS down properly? 160 ft-lbs seems to come to mind.
 
WJCO

WJCO

Meme King
I would start by having it balanced. I had a very similar symptom and I am fairly confident that it was a front pinion bearing. No play at yoke but when I removed the drive shaft, the noise went away. After regearing with new bearings, noise is gone.
 
HazMatJK

HazMatJK

New member
I'm pretty sure you need to adjust your Pinion angle closer to 5.5 -6.0 degrees, factory is somewhere around 4.5 if I remember correctly.
 
nmwranglerx

nmwranglerx

Caught the Bug
HazMatJK said:
I'm pretty sure you need to adjust your Pinion angle closer to 5.5 -6.0 degrees, factory is somewhere around 4.5 if I remember correctly.
Click to expand...

No you don't. If pinion angle is set to 6 degrees, caster would be at 0. Pinion angle from factory on a stock JK is about 2 degrees up. This gives about 4 degrees of positive caster.
 
JKbrick

JKbrick

Active Member
blackrubi14 said:
When I started I was measuring off the top of the ball joint, with a starting length of 23" eye to eye on my LCA's, I was getting a reading of 4-4 1/2. I started making the LCA's shorter and it helped the vibration, but did not cure it. I just measured off the flat circles on the front of the axle housing and it reads 89. This is reading with my iPhone.
Click to expand...

Your really close, 88 is the number you want for correct caster.
 
blackrubi14

blackrubi14

Member
So, I took my driveshaft to a local driveshaft shop to have them check the balance. $45 to check whether it needs rebalanced or not. I figure what the hell, check it out. They claim it was out of balance and the variance on the slip yoke was fifteen thousands out and they like to see more like five thousands.

I picked it up this evening and have not had time to put the driveshaft back in and run it (may not have time till the weekend). We'll see.......
 
blackrubi14

blackrubi14

Member
I finally had time this afternoon to put my driveshaft back in a go for a test drive, pretty much the same, the vibration isn't as noticeable but it's still there, and the noise is definitely still there.

Any suggestions on how to remedy this issue?
 
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