1996 GMC Sonoma

[lccent]

I have owned this 96 GMC sonoma for about 5 years now and it developed a vibration at high speeds after taking it for an oil change at a jiffy lube guy didnt know how to drive a stick slammed it on the ramps so hard front end came off the ground. Replaced u joints, had drive shaft balanced flywheel refinished new clutch ball joints and tires that have been balanced four times now took it to three shops including the dealer cant find anything that would be causing it even replaced one rim that was bent ( thanks jiffy lube). Its a 2 wheel drive 2.2L 4 banger Im stumped and out about 1400.00 checked rotors drums everything seems balanced but at about 55mph starts can feel it at lower speeds but not as bad and at about 70mph the mirrors are vibrating. I left it at one speed shop that builds race cars a friend of mine for 3 weeks cant find anything that would be causing it. I dont feel it in the stick its in the frame. tried rotating tires no different. replaced rear differential fluid no metal shavings replaced vibration dampener on drive shaft had it balance again. Im at a loss and Ive been dealing with this so long now I need a fresh set of ideas besides the obvious because its not the obvious?????????

[pm26]

Have you had the tires road force tested? This will determine the road force variation on tires if the belts have been damaged or tires are out of round.

[RevolutionRaceWorks]

is this an extended cab?