Hi Folks
Well I just (about two months ago) bought a beautiful '05 CXS that an old granny was unable to drive any longer (she had gotten too darn old

) it had only 10k miles on it and it is a STUNNER. I'm in love
However...
I recently had a transmission gasket and seal replaced due to a leak. There is now this whirring noise when I accelerate and it changes gears and shift poorly (it's an automatic). This reminds me of a neutral safety switch problem - AKA Speed sensor AKA Transmission Range Sensor. I've replaced them on Fords before. But that was after 150K not 15K.
I need some ideas fast. I had to beg buick to help with the cost of the gaskets and now I fear they may abandon me altogether.
I'll post again after I visit the dealer but I need some ideas (especially if anyone can say it is a sensor I can easily replace myself)
Help! Help! Help!