tlock, Some Oliver tractors have an auxiliary transmission called the Hydra-Power Drive. With the unit in under drive which is around 26 per cent speed reduction. In direct it has a straight thru power flow. Oliver also had a Reverse-O-Torc for the industrial tractors that was a forward or reverse like a modern backhoe. They also had a creeper drive but could only be used in 1st second and 4th gear. They also had a 3 speed Over-Under Hydraul Shift.