Is this a good idea?

[lukecp]

I posted a few weeks ago about a vibration problem i have been experiencing in my truck. The truck starts vibrating at about 75mph, and by the time i am pulling 85 or so it is unbearable. I have to pass on 2-lane roads alot, and in 3rd gear with the throttle wide open at about 95mph, it feels like the truck is going to fall apart.

Anyway....it may be either driveshaft or tire related. Since i'm not working right now, money is really tight, and i dont want to have to pay to get my tires balanced if i don't have to. So....can i jack the truck securley in the air, remove the rear tires, and possibly the brake drums, and start the truck, put it in gear, and rev it up until the speedometer reaches the speed at which i am experiencing the vibration? Would it hurt my driveline to be spinning at 85mph without any load on it?

This way...if i still had the vibration, i would know that it is driveline related....and if it is smooth, i will know that i need to get my tires balanced.

Thanks for any help