2000 chevy c2500 vibrates in the back at 60
 

At 55 it rides pretty smooth at 60 there is a vibration that seems to be coming from the back. I had a brake problem in the front so I turned the rotors and put new brakes on and that fixed that and thought everything was fine till I got it up to 60 and felt the vibration. It is not coming threw the stearing wheel. It happens when I hit the brakes too. not a terible bad vibration but shakes the mirors a little. any ideas were to start or just keep it at 55.

Change your ujoints, or it could be as simple as badly out of balance tire.

my thought also, my one other thought is the back drums worped?

Try rotating your tires... put the front on the back and the back on the front. Go for a spin to see if the vibration moves to the steering wheel.
If not in your steering wheel?
Move to the brakes... If you have enough drums left.. get the turned to see if they are out of round.
Keep us up to date on what you find.
I'd be curious to know what the issue was

Welcome to Truck Forums Chris

I'd still check the Ujoints first thing.

Ok ill keep you posted going to work on it today

I agree Rusty.. I'm not discount your suggestion, I'm just adding to it.

Im nto saying you were, it't just that for me, I drive a lot of gravel roads here in Alaska, and the ujoints not only go out a lot, they are also easy to check :)

Ya, you can just crawl under the truck and (with both hands) grab the drive shaft close to either Universal joint bearing and try and move the drive shaft up and down. There SHOULDN'T be any movement.
Then while your still holding the DS see if you can get any movement by twisting it. left and then right.

Is that how you guy check your U Joints ???

yea, pretty much. If it only has a little wigle, i'll pull them out and take them about and theck them out, and repack them.