1999 Chevy Silverado vibration in drive shaft

I'm interested to find out what method you used to replace the u-joints? The method used to balance a drive shaft isn't much different than wheel balancing. The old timers would use hose clamps to balance the shaft instead of getting another one. I can tell you the method if it comes to that. Depends on your budget I guess.

Not sure what the name of the method is, I simply removed the entire drive shaft from the truck by removing the 4 bolts on the rear axel, then loosing the old U-joint, then I slid the front part of the axel out of the transmission. I then had the drive shaft with both front and rear U-Joints + the short 12" yoke piece that went into the transmission on the bench. From their I removed the clips on the old joints and pounded out the old caps. I basically then followed the reverse process to put the new ones in. Ps, I did try to mark the drive shaft and transmissoins with chalk as recomended however it wore off durring the installation of the new joints.

The reason I asked how you removed the u-joints was to find out if you used a hammer. You said you "pounded" it and if you did you most likely bent the drive shaft. It doesn't take much. I used a hammer years ago on a dodge dakota drive shaft and it displayed the same symptoms as yours. Drive line vibration only at certain speeds. That was before I was schooled and I can tell you I never did that again. Do you have a vise? You'll probably be doing the job again.

I have a 1999 chev, just changed steady bearing and rear and middle u joint, now I have a vibration, does any body know what might be wrong, thanks