When does it do this? I believe many of the higher speed (6, 8, and now 10 speed) transmissions have problems with this because they cant pick which gear to be in. If it is from a "stop" I suggest coming to a complete stop. My Ram with an 8 speed will try to start in second from rolling and I mean barely rolling stop. If you are easy on the gas it will stay in second but if you get on it at all it will rather aggressively shift to first. Coming to a complete stop makes it go away.