I've been having a tranny problems the last few weeks. Took it to the dealer, they suggest I switch to high perf. gear oil. So while I had the car up, I figured I'd change motor oil, tranny oil, and rear diff all at once. I changed to Amsoil 75W90 in the tranny and diff. and mobil 10W30 for the engine.
The transmission is 100% better, shifts are smoother, and less vibration.
Overall, the best 85 bucks I've spent in a long time.