I get a vibration starting at about 50 mph, getting significantly worse by
> 60 mph and continues for as much as 85 mph (haven't gone any faster than
> that). The tires have approx 15k miles on them so I got a wheel alignment,
> all tires balanced and rotated with no change. The rear tires had some
> cupping and couldn't be balanced so I replaced them both, but still have
> some vibration although not as much as before. I've recently changed out
> both rear u joints, had the rears brakes done, with new bearings and seals
> installed. With the truck up the hoist and the rear tires raised there is no
> vibration, rear drive axle looks good, and both rears tires spin smooth. The
> tranny was rebuilt about 4500 miles ago but the torque converter was not
> redone. Could it possibly be the torque converter? transfer case?
>Truck has a 350 with 700 tranny in it.