My son has a 91 civic. The other day he came home and parked as usual. When he went to leave, his auto trans shifter wouldnt come out of park and into other gears. Their is a shift key lock, and we can depress it and it comes out of park and runs through all gears with no problem. He can drive it fine up until he puts it back into park again. and then the shifter locks and will not move unless we put a key in the shift lock key slot and depress it so we can start the vehicle in neutral.. anyone with any thoughts on how to fix this would be GREATLY appreciated.