1999 Montana shift problem

[restoroddin]

If I get in and drive all day with no stopping and idleing, I have no problems. If I stop at the corner store and leave it idle for 2 minutes or more, it slams from 1st to 2nd, 2nd to 3rd. Doesn't shift hard while downshifting tho... and doesn't shift hard from park to 1st???? Once again the mechs. think I'm on crack. as they have found nothing. Also it only seemed to start doing this after the last time they flashed my computer. They tested the comp and said it is fine.

 

[Unregistered]

If I get in and drive all day with no stopping and idleing, I have no problems. If I stop at the corner store and leave it idle for 2 minutes or more, it slams from 1st to 2nd, 2nd to 3rd. Doesn't shift hard while downshifting tho... and doesn't shift hard from park to 1st???? Once again the mechs. think I'm on crack. as they have found nothing. Also it only seemed to start doing this after the last time they flashed my computer. They tested the comp and said it is fine.

I have the same problem, and I have talked to another 99 montana owner and it seems that the there is a seal in the transmission that is leaving fluid leak behind it and that what is the cause......Does it reset if you turn off the car and let it sit for a minute? You will need to have the seals replaced in the tran..

 

[jerryuus]

1999 shift problem

I have a 2000 Montana and it used to have a rough up-shift problem at times. I have heard it is the pressure relief valve located in the transmission.

 

[ewertro]

This is a common problem with this year of Montana. Mine did from about 3 months after I got it (used). It was fixed by replacing the shift solenoid. I had the local Pontiac dealer do the work, requires removing front driver side wheel, lowering the engine to get to the inspection plate, not foe the faint of heart..... Cost about $750 Canadian, no problems since......