Hot Rods Do I have a driveshaft problem?

I have a vibration under load. It's hard to tell exactly where it starts but I'd say somewhere in the 1600-2000 rpm range. The vibration seems to be about the same regardless of vehicle speed.

I had a driveshaft shortened & balanced and new u-joints installed to fit the build so I didn't suspect the driveshaft at first. After a while, trying to track down the vibration, I pulled the shaft and found brinelling on the rear joint in the caps that mount to the 3rd member. I replaced the joint but still had the vibration so I figured the problem was elsewhere.

Still searching for my problem I pulled the shaft out today and the new joint is brinelling in the same pattern. Neither joint has very many miles on it. Do I have a driveshaft problem?

 

First guess would be pinion angle way off ...

 

You definitely have a drive shaft problem, be it angle or something else. What does the driveshaft maker say?

 

Drive shaft angle should be no more than about 5 degrees included angle and the engine and trans should be the same angle. Here is a video that helps explain it.
http://www.macsmotorcitygarage.com/2014/07/26/video-driveshaft-angle-and-phasing/

 

I agree, the problem is most likely the angles of the setup. A mismatched driveline angle setup will cause your problem.
Study that video, the angle of the transmission output must match the pinion angle.

 

I've checked the phasing. It's not perfect but the trans and pinion angles are within about 1 degree of each other. I didn't think that would be enough to cause a problem. I'm taking the driveshaft and both u-joints to the folks who made it tomorrow?

 

Yoke(s) must be perpendicular to the shaft (90*) as well as the phasing of yokes.
Pinion angle as mentioned above. I think you are on the right track to have the
shop double check their work. It may be elsewhere, but that is a great start to
tracking it down.

Ray