I have a 3/4 ton 1946 Chevy longbed pickup. I am running a 261 motor and have recently replaced the old unsynchrnized tranny with a Borg Warner T-5 five speeed, had a new drive shaft made and balenced then replaced the 4.56 ratio third member withqa 4.11 taken from a 1965 3/4 ton. I am getting the speeds (about 65 MPH) that I'm looking for but still getting allot of vibration. Anybody ever run into this situation. Can anyone give me a hint where to start?