Gear Vendors and one piece driveshaft problem

[arcticatdan]

Installed a Gear Vendors Overdrive in my 2000 Ford 7.3 crew cab short box 4X4. Installed a one piece driveshaft. I now have a vibration in the drive shaft that I can not get to stop. I changed the pinion angle up 2.5 degrees and also tried 2.5 degrees down, still there. The angles do not seem to be bad when looking at Spicer’s driveshaft guide. Has anyone had this same problem?

 

[hce]

How long is your driveshaft? Does the vibration go in and out? Is the vibration at a certain speed?

 

[arcticatdan]

The vibration starts a 60. The length is 53" center to center. The angle of transfer case is 5deg down and driveshaft 6deg down and rearend is at 7deg up. I did change the rearend from 5deg up to 0deg with no change. The vibration does get less at 70 to 75 mph.

 

[flareside_thun]

Where did the driveshaft come from? Sounds like it may be out of balance.

 

[Matrix37495]

Does the drive shaft have new u-joints? I've heard a few times that they hate changing operating angles.... Something to think about if its a used shaft...

You must be registered for see images attach

 

[arcticatdan]

Shaft is brand new. Balanced and rechecked a week later. Thinking about having an aluminium shaft made, but a big gamble at $500.

 

[hce]

I would second the out of balance. I had a driveshaft act similiar. Put in different u-joint sent it to a different shop to balance and now it is fine.

 

[Double-S-Diesel]

mayn have to go to a double cardiagn at the front

 

[Deib]

mayn have to go to a double cardiagn at the front

You can't because the GV is a slip yoke output.

I fought mine, found the driveshaft yoke were welded 3 degrees out of phase with each other, not much and couldn't notice it with the eye but that fixed it for me.

Leave the rear and at 0 degree angle, the 1 degree difference at the front is actually a lot. You may have to build a custom cross member to lower the transfer case a little and get that down to about 1/2 degree if you want it to go away completely.

It really won't hurt anything if you want to leave it.

 

[arcticatdan]

Had driveshaft rebalanced at another shop today. Installed it test drive almost smooth. Rotated rear u-joint 180* then bad again. Put it back to original position and rotated front u-joint 180* and almost smooth again. I am thinking maybe bad rear u-joint from new?

 

[hce]

Had driveshaft rebalanced at another shop today. Installed it test drive almost smooth. Rotated rear u-joint 180* then bad again. Put it back to original position and rotated front u-joint 180* and almost smooth again. I am thinking maybe bad rear u-joint from new?

Rear yoke may be questionable. Dial Indicators are nice here to measure run out of the driveshaft, rotate it in the yoke and see if it changed.

 

[arcticatdan]

Installed new u-joint and vibration almost gone. Changed the rear pinion angle again both up and down 1.5 degrees. Still have same vibration. Don't know where to go now. I am thinking drive line might just be a bad one. Everything I have done to date has not helped at all except the new u-joint, and the rebalance at different shop.