Pontiac Repair: Car shifts hard into 3rd gear, grand prix gtp, rd gear

Question
Noticed today that my 2002 Grand Prix GTP 3.8L Supercharged shifted hard into 3rd gear and the engine light came on. Now the car won't upshift into overdrive either at cruising speeds. Please help? What is going on with this thing?. Thank you...

Answer
Hi Dan:

well I would suspect the hard shifts were caused bt a bad pressure control solenoid in the transmission along with a code p1811. That code will cause the hard up shifts. As for no 3'rd gear that can be a lot of things from a bad shift solenoid (different then a pressure solenoid) to a hard parts failure in the transmission. what ever this may be I'm sure it's not a simple fix. take it to one of the big box auot parts stores and have them scan it for codes and see what codes(S) are stored and then you will have at least an idea what the codes are and go from there.