I have a vibration at 10 mph coast or pull. 12 speed with crd92/93 camelback. Transmission just rebuilt rear rear just rebuilt. Vibration was there prior to both trans and rear rebuild. Pulled drain plug on front diff and had some small pieces on it. Taking it out this morning. If I find nothing there. What else can it be? Truck is short 176 WB so it has no carrier bearing. I find it hard to be a tire at that speed. The vibration does come back at 45mph. You can free rev the motor an runs smooth. You can put splitter in N and run through the gears and it is smooth. I'm loosing sleep at night.