driveshaft vibration

[JPitha]

O. K. I have replaced 4 u-joints; 3 on the rear driveshaft and 1 on the front (forward of transfer case ) driveshaft, but still have a pretty good vibe between 40-55 mph. had the truck on jack stands, ran it up to 55 mph and could see the rear most driveshaft vibrating. no noticeable vibes at 65 mph. so what is it, and what do I do ??

 

[DTangstrom]

Check to make sure the shaft is not dented, bent, or missing any weights. Is that a lift kit in your signature, could the drive shafts be at an improper angle. Also check to make sure the axle has not walked or that there are no broken leaf springs. If the shaft is clean and the above does not apply try putting a large hose clamp on the shaft about six inches from the yoke and run the truck if it still vibrates as bad or worse move the screw part of the clamp 90 degrees from the first location and check again. Continue to to move the clamp untill you reach 360 degrees or the vibration gets better. If the vibration gets better but is still present try adding a second clamp at the same position. Hope that is of some help.

 

[JPitha]

Thanks. I'll try anything at this point. JP

 

[JPitha]

Thanks. I'll try anything at this point. yes, rev-tec level kit. also ride rite air springs. had them on for awhile with no vibes. vibes came after u-joint replacement. marked all shafts, so not out of phase, but had to heat yokes to get caps out... ... wonder if I gave it to much heat?