Driveline Vibration with 37’s

[Shootist]

Before I would drop the driveshaft again I would get the protractor and check pinion angle. It would take less time and at least rule out pinion angle as a concern.

Sponsored

 

[Gem1n1]

Before I would drop the driveshaft again I would get the protractor and check pinion angle. It would take less time and at least rule out pinion angle as a concern.

i have one of those digital magnetic angle blocks. I’ll post findings. Where do i measure?

 

[Shootist]

Get the angle from the pinion on both the transfer case and the pinion on the differential. Then get the angle from the drive shaft. It is a simple thing to check and as level of ground as possible. I sent a link to a good article previously but basically you subtract the Driveshaft degree angle from the pinion angle. So TC pinion degree from zero - driveshaft degree = front angle repeat the process for the differential pinion. They should be identical. If they are not then somehow the rear axle was twisted during the installation of you lift kit. Again, doesn’t make sense that it would be that but it is a simple check and worth ruling it out.

 

[Gem1n1]

Get the angle from the pinion on both the transfer case and the pinion on the differential. Then get the angle from the drive shaft. It is a simple thing to check and as level of ground as possible. I sent a link to a good article previously but basically you subtract the Driveshaft degree angle from the pinion angle. So TC pinion degree from zero - driveshaft degree = front angle repeat the process for the differential pinion. They should be identical. If they are not then somehow the rear axle was twisted during the installation of you lift kit. Again, doesn’t make sense that it would be that but it is a simple check and worth ruling it out.

 

[Gem1n1]

Took a quick video of the carrier bearing play. Is this amount of movement normal?

 

[Renegade]

Get the angle from the pinion on both the transfer case and the pinion on the differential. Then get the angle from the drive shaft. It is a simple thing to check and as level of ground as possible. I sent a link to a good article previously but basically you subtract the Driveshaft degree angle from the pinion angle. So TC pinion degree from zero - driveshaft degree = front angle repeat the process for the differential pinion. They should be identical. If they are not then somehow the rear axle was twisted during the installation of you lift kit. Again, doesn’t make sense that it would be that but it is a simple check and worth ruling it out.

Except that it’s a 2-piece driveshaft, which isn’t even straight from the factory. Lay under your Jeep and look. They aren’t even in line horizontally...
CVs shouldn’t have vibration at angles like u-joints, unless the CV goes bad.

 

[Shootist]

Except that it’s a 2-piece driveshaft, which isn’t even straight from the factory. Lay under your Jeep and look. They aren’t even in line horizontally...
CVs shouldn’t have vibration at angles like u-joints, unless the CV goes bad.

I understand what you are saying but is there not still some tolerance limit on angle? Mine is at stock height still but the pinion angle from mine and what I see in the pictures above indicates there is a large difference. My diff angle and driveshaft angle are very close to dead on. I can’t find my protractor to get the exact measurement for you at the moment. I have the same amount of play in my carrier bearing.

 

[Alabama Mud Machine]

That rear pinion looks to be angling 4.0* downward (nose-down) in this picture...Or is it just the angle which the picture was taken? If that’s the case, then that’s likely your problem... The pinion is NEVER supposed to be nose down.

 

[Alabama Mud Machine]

Took a quick video of the carrier bearing play. Is this amount of movement normal?

Looks beyond excessive to me. But I’m basing that on other vehicles, as I’ve never messed with my JTR’s carrier bearing.

 

[Shootist]

Is it possible the control arms sent in the kit were the wrong length?? Maybe when they were installing g the kit they left stock length arms in place?? This is of course just all guessing for me and not seeing it first hand but if someone else could get the angles on the rear diff and the driveshaft that is running the same kit it would be a very helpful comparison.

I moved my driveshaft in the carrier bearing and while it is hard to say if it is equal as I don’t know how much effort you are applying I can say that I have A pretty good amount movement with mine without excessive effort so I can’t say one way or the other if that is or is not excessive.

 

[Shootist]

From the pictures right you have 4.0 and 7.4 on the rear driveline giving you a pinion angle of 3.4. From what I know about things that is 1.4 degrees too much angle. CV style joints and the rear axle to driveshaft alignment is recommended to be no more than 2 degrees unless that is different on the Jeeps. I will find my protractor today and get my pinion angle for you that should help rule it out because if the kit was installed properly and the parts were the correct parts then that angle should have stayed stock.

 

[Gem1n1]

From the pictures right you have 4.0 and 7.4 on the rear driveline giving you a pinion angle of 3.4. From what I know about things that is 1.4 degrees too much angle. CV style joints and the rear axle to driveshaft alignment is recommended to be no more than 2 degrees unless that is different on the Jeeps. I will find my protractor today and get my pinion angle for you that should help rule it out because if the kit was installed properly and the parts were the correct parts then that angle should have stayed stock.

that would be awesome. Thanks.

 

[kelkolb]

Is it possible the control arms sent in the kit were the wrong length?? Maybe when they were installing g the kit they left stock length arms in place?? This is of course just all guessing for me and not seeing it first hand but if someone else could get the angles on the rear diff and the driveshaft that is running the same kit it would be a very helpful comparison.

I moved my driveshaft in the carrier bearing and while it is hard to say if it is equal as I don’t know how much effort you are applying I can say that I have A pretty good amount movement with mine without excessive effort so I can’t say one way or the other if that is or is not excessive.

Rear arms don’t change with the Mopar lift and the front LCA’s wouldn’t effect rear driveline angles.

I’ll take a look at my carrier bearing play since I’m on Mopar lift as well.

 

[Renegade]

From the pictures right you have 4.0 and 7.4 on the rear driveline giving you a pinion angle of 3.4. From what I know about things that is 1.4 degrees too much angle. CV style joints and the rear axle to driveshaft alignment is recommended to be no more than 2 degrees unless that is different on the Jeeps. I will find my protractor today and get my pinion angle for you that should help rule it out because if the kit was installed properly and the parts were the correct parts then that angle should have stayed stock.

That sounds appropriate for a driveshaft with a double cardan joint on one end and a Rzeppa CV at the other, but our rear shafts have a Rzeppa at both ends. These style are said to operate acceptably at up to 7 degree angle (actually there is some material which suggests 45 degrees is the max operating angle).
It’s just incredibly difficult to diagnose these type vibrations on the internet. Consider that there are hundreds (if not thousands) of us on here who have lifted JTs with no driveline modifications necessary. Why would this single Jeep require one? Seems to me that it is more likely that something is loose or damaged rather than it being a geometric problem.

 

[Shootist]

Well it sounds like the driveline angle should be good then. These other guys know Jeeps better than me so if that isn’t an issue and you have no vibration with the driveshaft out it may be the TC. At this stage I would just drop it at the dealer and say fix it. It is covered by warranty correct?

Sponsored