Drivetrain vibration.... Out of ideas

[Arcane]

Patient is OBS Tahoe 99 4wd.
Have a minor vibration til' 60 mph. 60+ is like a chisel hammer in hands. Wheels and tires are balanced, new rotors, pads, cv joints, hub bearings, upper ball joints, both new GM front and rear driveshafts, new front Bilstein shocks. Arm bushings are fine, wheel alignment\castor procedure done. I tried a road test shifting in Neutral on speed, even tried to turn off the ignition, effect = 0, still the same. So the problem is after transmission. I'm out of ideas....

 

[SCOTTYINWV]

Do you have the u joints in phase?

 

[Arcane]

Do you have the u joints in phase?

U joints are new GM, came with the driveshafts assembly

 

[Bearcat91]

How do the tires look? GF had a car where a tires belt shift and had a bad vibration. But you could feel it slow down and speed up as you speed changed

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[Arcane]

Tires are 2yrs old, about 7000 miles passed. Proteсtor wear is even. No sidewall bumps.
Also checked front axle mount arm bushings. Nothing bad discovered.

 

[SCOTTYINWV]

A belt can be busted in the tires on the tread and bulge to the inside of it. It happens all of the time. Take it to a tire shop and have them break them down and feel inside.

 

[94Sierra4x4]

A belt can be busted in the tires on the tread and bulge to the inside of it. It happens all of the time. Take it to a tire shop and have them break them down and feel inside.

And if it isn't that? Throw the tire back on the rim and throw your money in the garbage!
Just kidding, but I wouldn't take my truck to the tire shop for that, sounds like unneccesary down time for a shot in the dark.

Could be u-joints..
Vibration will pick up with increase in speed, then flail all over hells half acre when its unhappy, like your 60+ chisel hammer in hand effect

 

[sewlow]

These trucks suffer from a condition called 'beam walk'. I've been through everything that you have done, with the same results. Which is, no results!
GM is aware of this prob. Their solution? Carry 500lbs of ballast! WTF?
Only sure cure that I found, & I've done this to my '98, is boxing the frame from the rear cab mounts to the last box mount. Yea, I know. Not everyone has the equipment, ability, or even the time for that. But, it does cure the prob.
Other than that, I'd be checking the tire carcass' for separation. After all you've done, it's about all that I think that you could check, without going whole hog on the frame.

 

[94Sierra4x4]

When were the tires/wheels balanced?
How old are the tires?

 

[dowsewashere]

If you have the g80 it could be eating itself apart.