I was backing up in traffic and when I turned the truck to drive it would not shift into drive. The truck reved up like it was in neutral or park and wouldnt move forward. I had to put the truck in reverse again and then back in drive a second time to get it to shift into drive. This incident almost caused a wreck, because the truck would not shift into drive and move. The traffic coming from behind had to stop to keep from hitting me because the truck wouldnt shift into drive and move forward.