is this covered under the powertrain warranty?? took my truck in for an awful vibration and metal on metal noise. . they dropped the transmission all was well with transmission and tcase. . told me the clutch was the problem. . while appart they noticed some oil on the backside of the engine. rear main seal needed replaced. put it back togther and then noticed that the u joints on the front drive shaft where shot... only been on the road for 42000 miles in about a year and a half . Anyhow come to find out the vibration was the drive shaft this whole time. . anyhow wondering what you all consider warranty items??