2000 Impala In and Out of OD constantly

I have a 00 Impala 3800 190k, and sometimes when I am driving it shifts through all of the gears fine and then it starts shifting in and out of overdrive constantly. It does not quit until I shut off the car and let it sit for a while. Thanks Any help apprieciated

I have a 00 Impala 3800 190k, and sometimes when I am driving it shifts through all of the gears fine and then it starts shifting in and out of overdrive constantly. It does not quit until I shut off the car and let it sit for a while. Thanks Any help apprieciated

YOU MUST HAVE A TRANSMISSION SHOP LOOK AT THIS QUICKLY..

operating the vehicle with this and for sure the transmission will be destroyed...

with the mileage and with how the average owner maintains his vehicle it probably is already cooked...

the GM owners manual states that normal operation requires transmission fluid replacement at 100,000mi.. this is how many get into tranny issues....also dexron III which was used in your vehicle is not the best for your tranny...dexron VI is now the correct fluid..

I had the motor replaced in March 08 (mine had 153K when it died) and ever since then it does it every once in a while. Just recently it started doing it more then before. The motor is out of an 05 Impala that a tree fell on, the motor itself only has roughly 61K on it. (My motor was unfortunately not one of the unstoppable 3800's) I had the transmission fluid and filter changed by a transmission shop where I live. I did this a month after I got the car and it only had 116K but that has been about three years ago. I also had to have a sensor in the tranny replaced in 07 that caused the car to jerk really hard when it shifted.