I just recently had my transmission rebuilt and have already had it back in twice. Once was because it vibrated when there was a lot of wieght in the car and the second time was becuase my car would no longer move in reverse. Now it shifts fine from first to second, then when i shift from second to third it does one of two things: it either makes a terrible "clunk" sound when it shifts, or the rpm's just keep going up and it will not shift on its own until i let off the gas. It is a 98 gp gt with 130k miles and the tranny was just rebuilt about 3-4k miles ago.