Rear driveshaft vibration solved

[Agger]

Hey all. Hopefully my first post will help someone out. I've gotten a ton of good info here!

I'll make a short story long: I am rebuilding my 2003 TJ, swapping out PO's parts with new. I swapped out the 4" lift springs, stock control arms with adjustable, removed TC lowering spacers, installed sye kit and cv driveshaft.

I spent most of a day adjusting control arms back and forth from + .5 degree to -2.5 degree, but just could not get rid of vibration. (It vibrated pretty bad over about 35 mph.) To make sure it was in fact the driveshaft, I removed the rear driveshaft and drove in 4 high. Vibration gone.

I found the specs for driveshaft run out (.020") in the service manual and checked the shaft. There was about .012" in the rear end of the shaft, and about .030" in the front end of the shaft.

I removed the double Cardin joint from the TC output yoke and rotated half a turn. When I was cleaning up the yoke, I noticed a burr that 'may' have kept the u-joint from seating properly, but I don't think so. Either way the runout after reinstallation was arout .010", and the vibration was gone.

Phew!

 

[TJ2]

Hey all. Hopefully my first post will help someone out. I've gotten a ton of good info here!

I'll make a short story long: I am rebuilding my 2003 TJ, swapping out PO's parts with new. I swapped out the 4" lift springs, stock control arms with adjustable, removed TC lowering spacers, installed sye kit and cv driveshaft.

I spent most of a day adjusting control arms back and forth from + .5 degree to -2.5 degree, but just could not get rid of vibration. (It vibrated pretty bad over about 35 mph.) To make sure it was in fact the driveshaft, I removed the rear driveshaft and drove in 4 high. Vibration gone.

I found the specs for driveshaft run out (.020") in the service manual and checked the shaft. There was about .012" in the rear end of the shaft, and about .030" in the front end of the shaft.

I removed the double Cardin joint from the TC output yoke and rotated half a turn. When I was cleaning up the yoke, I noticed a burr that 'may' have kept the u-joint from seating properly, but I don't think so. Either way the runout after reinstallation was arout .010", and the vibration was gone.

Phew!

Welcome to the forum. What's your rig looks like? Just to let you know there is a rule here.

 

[Jerry Bransford]

Hey all. Hopefully my first post will help someone out. I've gotten a ton of good info here!

I'll make a short story long: I am rebuilding my 2003 TJ, swapping out PO's parts with new. I swapped out the 4" lift springs, stock control arms with adjustable, removed TC lowering spacers, installed sye kit and cv driveshaft.

I spent most of a day adjusting control arms back and forth from + .5 degree to -2.5 degree, but just could not get rid of vibration. (It vibrated pretty bad over about 35 mph.) To make sure it was in fact the driveshaft, I removed the rear driveshaft and drove in 4 high. Vibration gone!

Setting the rear pinion angle isn't a matter of trying different angles, it's getting it to the same angle as the driveshaft when you have a CV driveshaft with a SYE.

But you ultimately found that the u-joint wasn't seated properly which positions it out further to the side which will definitely cause major vibes. Good job finding it.

For those who can't picture the problem, here's what it looks like...

Getting your pinion angle matched to the driveshaft will cure any vibes associated with an incorrect rear pinion angle. Your rear pinion angle must look like this. The pinion angle can err slightly like pointing 1 degree lower than the driveshaft but it cannot point even 1 degree higher than the driveshaft.

 

[Fouledplugs]

Setting the rear pinion angle isn't a matter of trying different angles, it's getting it to the same angle as the driveshaft when you have a CV driveshaft with a SYE.

But you ultimately found that the u-joint wasn't seated properly which positions it out further to the side which will definitely cause major vibes. Good job finding it.

For those who can't picture the problem, here's what it looks like...

View attachment 68881

Getting your pinion angle matched to the driveshaft will cure any vibes associated with an incorrect rear pinion angle. Your rear pinion angle must look like this. The pinion angle can err slightly like pointing 1 degree lower than the driveshaft but it cannot point even 1 degree higher than the driveshaft.

View attachment 68879

That must be a really old camera you have. Or copied and pasted. Pretty pixelated to say the least.

1 degree lower is what Ive always read.

 

[TJ2]

Way better than no picture at all.

 

[Fouledplugs]

Way better than no picture at all.

 

[Jerry Bransford]

That must be a really old camera you have. Or copied and pasted. Hard to see details in that picture. Very pixelated to say the least.

What image are you referring to? What I posted is extremely sharp and clear on my large monitor.

 

[TJ2]

It's extremely sharp and clear on my large monitor.

It's sharp on mine as well Jerry. Fouledplugs, are you sure you have your eye glass on?

 

[Agger]

Yeah, I understood that part... I just figured I was off a bit measuring, or hadn't gotten 'just right'...

 

[Fouledplugs]

Yeah, I understood that part... I just figured I was off a bit measuring, or hadn't gotten 'just right'...

Congrats on getting rid of the vibe.

 

[Agger]

Welcome to the forum. What's your rig looks like? Just to let you know there is a rule here.

Duly noted! Thanks.