87 n/a auto, my car vibrates like hell between 55 an 70 mph. It doesn't matter if the car is in 2, 3, OD, acelerating, decelerating or cruising. What is wierd is that it doesn't do it all the time and when it does, if I put the car in neutral and let it drop down to idle, put it back in gear the problem is gone. I don't believe it is the drive shaft or rear diff. because it goes away in neutral. I don't believe it is the engine because it only happens 55 to 70 mph regardless of rpms. Any clue what is going on or what I should check?

 

well if it is the trans, installing a 5 speed manual is the best solution.l

 

I once heard that going from AT to manual or switching the tranny is not a good idea... is this true?

 

i would definitely check the driveshaft, get under your car and check and see what kind of play your u-joint has.