Truck shakes at 65-70mph

[Donnie Yukonie]

I've got a '99 1500 Suburban, that I bought in 2000, and have the same issue.
I've changed 3 sets of wheels, 4 sets of tires, Brake rotors, tie rod ends, 3 different brands of shocks, multiple alignments and balance jobs....ease up to 66 and TADA there it is. Flabber gasted I am.

u joints?

 

[Doverpoint]

I had this exact same problem. I ended up replacing the drive shaft. Hard to believe, but they do go bad. When you replace the drive shaft make sure you buy high end universal joints, and while you are at it, make sure the fluids in the transfer case and the rear end are changed and at the correct levels. Good luck!

 

[mhorn0817]

welp, turns out tire balance was the issue. although i balanced the tires a year ago, a sticky weight must have falling off because one of the wheel was 5oz out