I have found the wheel size to be different with the 70 ton having a little larger wheels. The gearing is the same. I have replaced the wheels/ gears with the Northwest Shortline ones, which will work with the 70 tonners, 44 tonners, dual motor, and even the newer 70 ton with DCC on board. The wheel sets are not cheap, and will require disassembly of the truck on the dual motor trucks, or removing the bottom plate on the DCC ones.