My trans shifts straight from 2nd to 4th sometimes. Light throttle it's fine, but the more I get into the throttle, the less time it stays in 3rd. Up to about 3/4 throttle, and then it goes straight from 2nd to 4th along with a good clunk. If I'm on it I have to shift to "D" until it gets to the shift point in 3rd gear. If I do this, everything works fine. It's been like this since I bought it 5 years ago from Premier Performance. They said they put a 4th gear upshift kit in it, and it's non-locking if that matters. Not sure what else they did, but I got no help from them. Just wondering if it's something that could easily be fixed. Or am I just SOL without taking it apart? Thanks.