Im thinking this might be eating my trannys, its been getting worse over the last few weeks. IVe been threw 3 trannys in the last 3 months. It vibrates really bad when im on it hard in 2nd and 4th and the alittle when im going over 65mph. It also does it alittle in every gear like when im driving in traffic but not bad. I was thinking it was the rear end or drive shaft since it does it over 65mph. But the 2nd and 4th vibration (shift shakes around alot!) when im on it hard confuses me, it doesnt do it in 3rd is whats strange. Im just changed the U joints the drive shaft and made sure it when back in the way it came out. A freind of mine that builds t-5s for spare cash went thew the tranny about 2 weeks ago put in a new 2nd gear and lower cluster. The clutch is about a year old, Piliot bearing was changed when i put this motor in about 6 months ago. Harmonic balancer is a stocker but it looks to be in good shape. Anybody have any ideas? Thanks James.