Vibration at 65-up or 2100-up rpm

[lt1transam]

Ok, its been doing this since I bought it 6 months ago. 99 Cadillac, brand bew wheels and tires, all new wheel bearings, front brakes, rear pinion bearing, ball joints. Rebuilt transfer case. Once I hit 65 or around 2100 rpm the steering wheel starts shaking like crazy. Tried balancing old tires, bought brand new wheels with Cooper Discoverers. Last thing I can think of mightbe the front drive shaft.

 

[SunlitComet]

or perhaps a loose steering part.

 

[qukon 95]

rag joint often it's over looked that it gets soft i replaced mine 2 yrs ago