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Pete, Pontiac Technician
Category: Pontiac
Satisfied Customers: 29097
Experience:  17 Years Pontiac Technician and training.
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Pontiac Grand Prix GT 04 gt transmission was shifting hard

Resolved Question:

04 gt transmission was shifting hard after going around a turn and accellerating now after driving 25 miles hard shifts after takeoff.turn car off and restart and is fine for a while. just had fluid and filter changed 105,000 miles on car
Submitted: 6 years ago.
Category: Pontiac
Expert:  Pete replied 6 years ago.
Hello,I will be glad to try and assist you with this,Welcome to Just Answer.


I just need a little more info to assist better.

Is or has the check engine light been on with this problem here?

If so have you had the fault codes checked in the computer systems?

Is this the super charged 3.8 liter or the standard 3.8 liter engine?

Let me know so we can continue,Thanks Pete!
Customer: replied 6 years ago.
no check engine light, no fault codes cause i reset the computer i think(disconnected battery), standard 3800. it acts like it is drifting around for the right gear or throwing overdrive on when it acts up
Expert:  Pete replied 6 years ago.

Two common components that can cause this problem here are first the transmission fluid pressure solenoid in the transmission valve body,this solenoid can stick and cause hard shifts like this.This solenoid may need to be replaced in the transmission to correct this issue.

There may be debris built up in the transmission valve body.If this is the case sometimes having the transmission flushed with a transmission flush machine at a shop or dealer can free up and remove most of the debris and may correct this.This would be the cheapest step to take here first.

Another component that could cause this is the transmission valve body or valves in the valve body sticking.The valves can bind on metal burrs in the valve body which can cause hard shifts,there are some bulletins out by GM for this concern to remove and disassemble the valve body to check for valve and valve bore issues,depending on how bad the damage is the valve body might be able to be rebuilt or it may need replaced.

Disconnecting and reconnecting the battery wont reset the codes on this vehicle.This has to be done with a scan tool that can communicate with the computers in this vehicle.But before you have the codes cleared out I would have the codes read out with a scan tool to see if any codes are set for this transmission fault.

This will aid and in some cases can pinpoint the failure,then it can be diagnosed and repaired once the fault is found.Most shops and dealers can check these codes for you and let you know what is needed.

From what is described here this sounds like the first couple of suggestions,a possible sticking pressure regulator or the valve body has an internal mechanical failure in it.

The cost for these repairs vary depending on what needs to be done and your location as well as the shops charges.It can range from $400 to over $2000 depending on the failed component.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
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