Or rotate the tires, and see if your shake is any different.

 

+1 i had a nasty shake at speed that went away after i rotated my front tires to the back. turned out my tires needed to be rebalanced

 

I'm voting unbalanced driveshaft, I had the same problems, except it started at 75, and a balanced driveshaft solved it

 

I had a bad vibration and shaking at 55+, then my rear u joint on my drive shaft blew out and now I'm in the hunt for a new one. Luckily it wasnt the front or i would have catapulted.. Crummy part is the u joints are 5 months old, I replaced them when I put the new rear in

 

What brand U-joints did you get? Did the joint fail? Or did some bolts come loose?

 

i guess ill start at taking a look at all my u joints in the front and the driveshaft then get the tires balanced and go from there

 

Check all joints and suspension for excessive play also.

 

Sounds to me like a couple of horney fat kids in the bed of the truck gettin' things done!

 

 

My buddy just bought a 02 cummins and it foes this too. At about 70, don't know what it is