I have a 98 2500 with the 12v. I had the transmission completely serviced. Get the truck back and drive it around and it doesnt seem to shift. Trans guy says its not the trans and its the motor. Gets to a certain point and falls on its face so to speak. Bring it to another trans guy and says same thing, not the trans but the motor. So it goes to my diesel guy. Diesel guy says its making the power. Last year we did the famous dowel pin, new injector pump and new lift pump. So we go to a new diesel guy for another opinion and says its making the correct fuel pressure and what not. Seems like the turbo is making the right pressure. Anyone have any other opinions. Its getting fustrating, dumping money into this truck and my 97 2500 with 360 out tows this truck.