Re: Truck vibrates at certain speed
You could many causes including a defective tire, bad shocks, improperly balanced tires (Sometimes tire jockeys lack proper training or experience) even water left inside the tire! (This happened to a friend) Check the tires for any obvious damage, such as cuts or missing treads, bulges, cracks indicating dry rot and or sun damage, exposed cords and any signs of the tread de-laminating from the carcase of the tire, usually caused by driving on underinflated tires. That is a good suggestion to move the tires front to back and visa-versa to see if it changes. If it remains the same, I would look to the u-joints or other mechanical areas. Check the front end (or have it checked) for worn ball joints, tie rods, idler arm, etc. and any signs of leakage on the shock absorbers. Even improperly adjusted wheel bearings.
As to AtlMax-I would bet that either the u-joints or the drive shaft it self was damaged during the repair. Needle bearings can be lost or damaged if the bearing caps are not held in place during the install and the yoke of the driveshaft can be bent if incorrect procedures were used during u-joint replacement.