1999 Grand Prix cold shifting problem

I have a 1999 Grand Prix 3.1 181,000, AT with Floor shift. And I live in Northern Minnesota

Starting last Spring when it was still cold out, when I would go jump in and start the car, when I would try to shift out of park it would not until the car warmed up about 5 minutes.

I brought it to the local GM Dealer and they thought it was "thick fluid" so they domped some "conditioner" into the transmission, charged me $80 and said it would clear up in a few days. Well it did not clear up, but then within a month it warm out and the problem went away. Drove it all summer and worked fine.

But now that the temp is dropping same problem. If the temp is below 40 degrees outside it will not shift until it warms up. I brought it to a transmission shop this time and they too said it was probably bad tranny fluid and did a flush, filter change and claimed if they put in synthetic fluid it would be fine.

But guess what, it's still happening. I then took it back to the GM shop and asked them to check if the Brake, shifter, interlock systemwas working correctly and they told me that if it will shift out of park once it warms up, then it can't be the interlock system, because if that was bad it would never shift out of park. They again wanted to change the fluid, but when I told then I just had that done and it didn't help, they said to make an appointment for someone to "do a fll maintenance check of the vehicle" which when asked about the price of such a thing, they claimed 4-5 shop hours plus parts for anything they find wrong. Well I haven't made an appointment yet. Does anyone know what this issue migh be? Thanks, Steve
Do you
have the same problem?
Saturday, November 10th, 2007 AT 5:54 PM

1 Reply

Are you saying that the shifter itself won't move? I am presuming that this has a floor shifter. Can you here hear any noise such as a quick click when you press the brake pedal and the button on the shifter?
If you can't shift at all and don't hear a click, then I speculate that the solenoid that unlocks the shifter isn't working correctly. If the cold temperature causes this, it sounds like it is dry and needs lubricated with something such as WD-40. The solenoid is a plunger type assembly that locks the shifter.
If you know how to take the trim off of the center console, you can access the solenoid in order to lubricate it.
It could also be a faulty ignition switch which gives the power to this solenoid when the brake pedal is pressed. Are there any other odd things happening with anything electrical?
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Saturday, November 10th, 2007 AT 6:32 PM

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