Car doesn’t like downshifting for hills...
Asked by Elijah May 04, 2020 at 01:03 PM about the 2008 Pontiac Grand Prix Base
Question type: Maintenance & Repair
When I’m going up a hill or even a slight incline the
car doesn’t want to downshift until I give it more
gas , or even when I want to pass someone on the
highway I need to punch it in order to down shift, I
don’t know if it could be the fuel filter or
transmission solenoids because sometimes it shifts
very smooth but other times not. ((3.8 V6))
8 Answers
Sounds pretty normal to me. Why do you think there's something wrong with the car? Scan it for trouble codes and have the transmission serviced if you want to be sure.
Did this just start doing this or has it been like this for the last few years? It is probably OK and factory set that way as a way to save gas. As munron said, have codes read and trans investigated at a reliable shop.
The car is only showing one code , Incorrect gear ratio/timing , I don’t know what that means and even when I put it in cruise the car still has problems downshifting.
Google the code to see what it means. What did the transmission shop say when you had it checked out?
The car jerks erratically if I do not for it to down shift , it will stay in fourth trying to go up a hill start bouncing terribly, then when the O/D turns off then goes into 3rd gear it’s completely fine, the “transmission shop” said the same code and suggested a rebuilt which I think it’s just solenoids
Well at least now you have some options. If you don't trust the transmission shop's appraisal take it to another one for a second opinion.. If it does need a transmission I would find a used one. An old base GP just isn't worth the cost of rebuilt transmission. If you're convinced its only solenoids even though the professionals think otherwise then start replacing solenoids. It's only money.
I’m currrntly bidding on a GP that’s has 101,000 miles on it and it’s supercharged with the HD transmission in it , and your right @munron the car isn’t worth a new tranny even if the engine is bulletproof, if I get this car I’m going to use the one I have now for parts because there’s just zero point
Glad to hear you made that choice. Good luck on the one you're bidding on. I had an '03 GTP for years and loved it. It's also a great starting point for performance upgrades if you're into that and if not its a strong performer just as it is. If you don't happen to get that one, keep shopping. There's still lots of low mileage GTPs around and for the most part they're not worth a whole lot so its economical transportation.
