Mark they used the 3 piece differential you see in the video and a single Detroit 6046 engine, the same power plant they used to re-power the Canadian Forces monument Sherman they subsequently stripped bare...but that is another story. Once they had the drivetrain installed they realized the differential turned the wrong direction giving them 5 reverse gears and only one forward gear. Instead of changing direction of the differential, which is relatively easy on the later one piece units or changing the rotation if the engine, which is even easier given Detroits ability to run either way by changing the timing gears, they instead added a remote mounted truck transmission and placed this transmission in reverse. As you can see hilarity ensued. Looks good on this group....