So i have the I-6 with the auto 3 speed, the other day i am driving i get onto an onramp and when it kicks into the higher gear i get the RPMs but hardly any acceleration, I can gradually get to the top speed. I get back to my garage, and i noticed i cant get the shifter into park. all other gears work fine...has anyone seen this? first thing come to mind is my tranny is shot...thanks in advance for any help!!

Dan