1999 Chevy Silverado vibration in drive shaft

make sure U-Joints are seated all the way and if they are then you can find a drivshaft shop to reballance the driveshaft and if problem persists then rotate tires and see if it changes to front I have had some that after changing U-Joints still had shake and turned out to be tire ballance

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