Ah, I thought you meant with cruise activated. My apologies.
What's the condition and level of the transmission fluid?
1. Drive around for 10 minutes in the city after the transmission is at operating temperature.
2. Park on a level surface and apply the parking brake.
3. With P selected, shift through every gear and return to P.
4. Pull the transmission dipstick with the engine idling, wipe it clean, reinsert it completely, and read the level. It must be within the notched areas labeled "HOT". Check for fluid contamination after wiping on a paper towel.
The fluid should be red, and not smell burnt. If it is, do a drain & fill or a cooler line exchange.