I am picking up our 2008 Prius with 42,000 miles in Charlottesville, VA to drive home. Our son has had it for three years and recently purchased his own car. I tried to drive it from the parking lot yesterday and it would jump out of gear after about 1 second in reverse. I held the shifter down in reverse and backed it out of the parking space after the battery performed a recal. It would not shift into park at all unless the power button was pushed to shut the car off. It did the same thing in forward, so I pulled it back into the parking space. The interior of the car was extremely hot. I could barely hold the steering wheel.It is a black car and the ambient temp was in the 90's. This morning our son came to pick us up at the hotel in it and it operated normally. We drove it back to his parking lot and left it while we did the tourist stuff today in his car. It sat in the parking lot until about 4:00 and I decided to fill it with fuel and put air in the tires for a road trip.. Once again, it would not stay in drive. I held it in drive for about 20 miles with the AC running on high. The interior cooled down considerably, but it still would not stay in drive. I left it again for about 45 minutes and tried it again when we left for dinner. It drove perfectly. I had Autozone hook the OBD reader up to it and it didn't show any codes. The voltage was checked and he said it was at 13.1v. The car will be 5 years old in September and I was suspecting the battery. There wasn't a battery for it anywhere in Charlottesville, so we will head home tomorrow with the original battery. I searched the internet last night and found the same issue in a lot of Gen II and in some Gen III. The repairs for the issue were sketchy, but some had said the dealerships had changed out the shifter and repaired the problem. The battery will be changed out when I get home unless I find one on the way home. Any ideas?