99 Grand voyager tranny problem

My wifes 99 grand voyager has a problem with the tranny. Sometimes (not all the time) the trans doesnt engage. When she comes to a stop at a light, it might not go until she turns off the engine and starts it back up. She may have the problem when she first gets going out of the driveway. Then she turns off the van and restarts it and it works fine. Does anyone know or have ,had this problem before:runaround:

Sounds like the solenoid pack to me. Have you checked the fluid level? that could be the culprit also.