I first noticed a vibration at 15,000 miles. I took it to the stealer and they could not hear what i was, so nothing was done. That was 3 months ago. As time went on i noticed it more and more, alot at 63 mph. I took it back to the stealer last week ( 20,000 miles ) went throu 3 tecs in three days and 3 trips back to take them on test drives to show them what i was hearing. They called me on friday and told me that the truck was fixed, come and get it. Sayed it was a u-joint, BS but ok, lets see. Drove home same s--t. Took it back monday morning and got the " its the tires" story again. Said they would put their expert on it. Got a call that night now the story is the rear end is worn out, daaa, thats what i told them three months ago. The mech said it looks like a unit with 150,000 miles. I have not done any real towing with the truck yet. Anyone have this before?