Drive Shaft Imbalance

[AJ168]

I did the U-joints on my rear drive shaft the other day and screwed up thinking that the drive shaft would pull out of the transfer case, when it really pulled out about a third of the way back. I had everything marked, except for right there. I was able to get it back close to it's original position, but it has to be off by a little. Going down the road, there's a slight vibration at 50 mph, then again at 70. It's noticeable, but only on a smooth road. Question is, is it worth pulling it back off and getting it balanced, or will my new u-joints and transfer case seal be safe with just a little vibration?

If I should balance it, is there any way i can make something up to do it myself?

 

[imp]

If I should balance it, is there any way i can make something up to do it myself?

Yes, there is. With all 4 wheels safely off the ground, if the driveline is run under engine power, a piece of chalk held very carefully and cautiously against the rotating driveshaft will reveal a "high-spot". In other words, the slight "wobble" of the spinning shaft causes it to deflect in the direction of it's heavy side, thereby causing vibration.

Ford recommends use of standard worm-gear hose clamps, large enough to encircle the shaft, placing the screw of the clamp OPPOSITE to the chalk mark. You might be able to detect the difference produced by first running up to the speed which produces most "felt" vibration, then check again at that speed for improvement, or degradation, after installing 1 clamp. Check with chalk after installing one, to learn if more are needed, or if 1 was too much.

I have done this, it is hit-or-miss, but sometimes helps. imp

 

[snoranger]

It sounds like you pull it apart at the slip joint. When you put it back together, did you put the U-joints in phase? If not, that can cause a vibration.

 

[AJ168]

No the u-joints were not in phase, but I'm fairly certain they weren't to begin with. Are they supposed to be?

 

[snoranger]

Yes, they have to be.