Went for a trip with my dad the other day and his 1999 grand prix 3800 v6 and the transmission is acting wierd. Here are the symptoms when it gets hot it "bangs into gear" when upshifting, shifts very hard. Downshifts seems smooth and fine. Also there is a whinning noise when starting out, not terribly loud of anything kinda sounds like a supercharger if I had to explain it. I asked him how long it has been doing this and he said a couple years. I was thinking adding a B&M supercooler, magnefine filter and a few pan drop fluid changes. Well, one then adding a drain plug to change fluid. Anyone know any known problems with these transmissions or cars? Thanks for any input.