no tranny pressure selinoid? ?

[08 gp lvr]

My 08 gp has been acting up lately, off the line it hesitates then goes in to gear pretty hard and recently has been slipping between gears. It only used to do it seldomy when hot but now seems whenever it wants. I've read many posts here and a lot point to the pressure selinoid. But from what I gather, my 08 doesn't have one. No trouble codes and I had my flush done when recemmended. Any ideas.....

 

[Fivefingerdeathpunch]

Your 08 trans is no different than a 06 or 07 and so from 04+. It has a PCS.

When it slips or does what it does it might throw some sort of code. Some tranny codes will go away if the shut the car off,

 

[08 gp lvr]

Thanks. Called the dealer and was told its inside on the valve body. Funny thing is there's no codes set making me think that it may lie in the shift or throttle linkage needing adjustment. Another reason I have read that these cars are prone too is valve body getting gummed up and not flowing properly thus needing an additive like w ynns. Would this be an ideal plan? I'm just so freak in scared, this is my baby

 

[08 gp lvr]

Has this happened to anyone else? My biggest problem is on take off. It will hesitate and go in very hard. I thank you for any input

 

[nik12937]

I personally would avoid additives of any kind. The throttle linkage doesn't exist technically, these are drive-by-wire engines, starting with the 04's.

When was the last time you changed your transmission fluid? The first thing I would do in your case is drop the pan (drains around 7.5 quarts I believe), clean the pan magnet, and change the filter. Fill it up with some Dexron VI transmission fluid. While you're in there you could also try throwing in a shift kit as it's not all that difficult to do. Installing a TransGo shift kit got rid of my hard shifts, but I did eventually have to do a little work on the valve body. My PCS solenoid was the culprit, but I replaced and upgraded a few other things while I was in there.

This will give you an idea of what it takes to get to the valve body if you go that route: http://www.grandprixforums.net/threads/54448-How-to-transmission-4th-gear-side-cover-access

For now try a fluid and filter change though, for all you know it could just need new fluid. I have on a few occasions had transmission problems vanish after a fluid change, just not on my vehicle.

 

[08 gp lvr]

Thank u much, I changed my fluid at about 100 000 kms. It now has 150 000.When ur pcs solisolenoid was bad what was ur problems? Did they resemble mine? Im gonna look at that video, but will that kit make my tranny switch gears at a higher rpm's? Is this valve body thing able to come out of the trany so I can clean it?

 

[08 gp lvr]

Just wondering if my pressure sensor was bad, would it trigger my cel?

 

[nik12937]

When mine was bad it would slip into first gear, usually when hot after driving for a while. It would also have very odd shifts in general, slow sometimes and very harsh at other times.

The shift kit will only give you quicker, former shifts, the RPM's and such can only be altered by an aftermarket PCM tune.

When I did work through my side cover, I took the channel plate and valve body out as one unit to work on a table. I then seperated them, taking care not to lose/drop any check balls. You'd need new channel plate gaskets and valve body gaskets as you can't reuse any of them. I only cleaned the mating surfaces where the channel plate gaskets sit since the gaskets sort of bake into place after a while. Some careful work with a razor blade got it all off nicely.

It usually won't trigger a CEL from what I've seen, the codes do pop up, but only until the next restart. Probably what made diagnosing my problem so difficult, I never had my scanner on hand when it would happen.