94 GMC truck
I have a 94 GMC 3500 crew cab dually truck. Shifts normal but, when it gets to a stop light for example; it will not shift. I have to pull to the side of the road to turn the truck off and when I restart the truck it shifts fine again for a short while until the problem continues with the truck not shifting. Has anyone experienced this problem or have an idea of what it could be? I have taken it to three mechanics and no luck.