2001 Durango shift to low 4wd

My 2001 Durango R/T 5.9 L shifted into low 4wd without any help. This happened twice since it was new and the dealer has no idea why this would happen. The shift indicator shows both lights when this happens and the switch was never touched. Both times it yhappened while going 30 MPH and it is quite a ride. I can't wait for it to happen at 70 MPH. I would suspect that the transmission will self destruct. The answer men at Chysler have no answers either. They just say they have never had this occur before. The computer shows no errors and in order to get the transmission back into the correct mode you need to stop put the lever in neutral and turn the switch to the low 4wd indicator position and then back to the awd position. The light for the low 4wd indicator goes out and the awd position indicator light goes on again by itself. Are there any suggestions out there for this weird occurrence?????