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JDS 4x4 · (This post was last modified: 10-26-2011 03:58 PM by JDS 4x4.)

Hello, ill start off with a little detail on my truck, I have a 2005 Dodge 2500 4x4 QC LB with the Hemi, I have a 6 inch lift and Brand new 37x12.50-17 Cooper Discoverer STT's. Ever since I put my lift on I've had a vibration from the front drive shaft, I take ot out and its just fine, I know its not tires, I've had 3 different sets on since I installed the lift, just had a alignment and new u joints installed in my front drive shaft and its still the same so currently running no front shaft, anyone have this problem or know what it maybe?

Tango · 10-26-2011, 04:01 PM

The slip on the drive shaft "has to go" back exactly were it was oringially at. A possibility is the drive shaft was taken apart without marking it first and then put together not in the same position, so then your front shaft is no longer balanced. You can remove the shaft and have it re-balanced.

JDS 4x4 · 10-26-2011, 04:12 PM

Well the vibration was present before the u joints and when I put the lift on I left the drive shaft in and didn't remove it, as far as the slip part of the shaft I know it isn't in the same spot its extended out probably about 1" to 1.5". I did notice that it seems where the slip section is it has a little play in it, not sure if it's due to being extended out or if its worn, the truck has 126,000 miles.

Tango · 10-26-2011, 04:41 PM

Then it could be either a bad u-joint or the front axel wasn't angled/shimmed right.

Extending the shaft is not going to change the balance, it is when it comes apart and going back together in a different position. Since the shaft didn't come apart that is not the problem.

It depends on what lift you have, but they usually rotate the front axel a little to line the angles of the driveshaft back up. On a leaf lift they are shimmed and on a coil lift I think the arms are adjusted to rotate the axel a little. If the angle is off it will cause a vibration.

Did you replace the u-joints on the front drive shaft? If not a bad u-joint could be the issue.

JDS 4x4 · 10-26-2011, 05:00 PM

Yeah it has new u joints in the front drive shaft with about 2 miles on them, and I pulled the shaft back out since it still has the vibration. With winter nearing I need to get this fixed

Tango · 10-27-2011, 04:03 PM

With new u-joints then it is likely not a u-joiunt issue.
(though you can install new but bad u-joints)

Since you installed your lift, read the part about adjusting the axel angle.
For example if you are standing beside your truck at the passenger side, then there should be some instructions on how to rotate the front axel slightly clock-wize. I may need 1 or 2 degrees rotation. See the directions.

Do you have leaf springs on the front? If so they make angled shims that come in sizes like 2.5 degress or 1.5 degress. You install the shim between the axel and leaf spring with the fat part of the shim toward the front of the truck and it then brings your axel-angle back in line with the drive-shaft.

When you installed a 6" lift it changed the angle of the drive shaft with the angle of the front axel.
I am not familiar with your exact lift kit.
BUT
Each lift kit has a way to bring the axel and drive shaft angles back into tolerance.
If the axel drive shaft angle is out of tolerance it will cause the problem you described.