Bad Vibration

Just a couple of weeks ago, my blazer started vibrating pretty bad on the freeway. It sounds/feels like its coming somewhere on the driveline but im not 100% posotive. I took my driveshaft to the shop where they replaced the front and rear u-joints and also balanced the shaft. Got on the freeway and it was still there. Maybe a bad tranny mount or something? Any ideas would be appreciated.

Check your tires for the righ pressure.

Have them balanced and rotated.

Would it be my tires even though it feels like the driveshaft is bouncing up and down? And also right before it does that, the tranny makes a slight clunk then it starts vibrating.

Check your transmission mounts.

Well I crawled under my blazer and discovered that the tranny mount only had one bolt in it. So I replaced the transmission mount and bought two new bolts, put it all together, and it still vibrates like it used to. Any new ideas anyone?

Howdy, you need to check your tires for a busted belt and check the balance on them. Could have lost a weight.