I have a 94 F-150 with 4.9 and a E40D. There is a vibration between at all speeds. It does it with a load on while gas, especially on OD. It goes away when let off gas.

A few months ago I haved some rough Idle problems and when I put it on gear (reverse gear especially) was very rough. I did change the "manual level position sensor " that took care of it.
Now it is rough when put it on drive only and the vibration that I mention early. Any help you can give me would be greatly appreciate.

 

Check your U-joints, they may be worn. Lay under the truck and rotate the drive shaft slightly. If the drive shaft has any play that does not move either the tranny yoke or the pinion shaft at the rear end, you need U-joints.