Twin
Disc 2000 Series Allison Twin Turbine TransmissionsThe 2000 Series Twin Turbine Principle: Twin Disc 2000 Series transmissions contain twin turbine torque converters, one inside the other. Each turbine drives a different combining gear which drives the forward-reverse range gears.
When the load is started, oil flow within the converter causes the first turbine to turn, driving a low speed combining gear which in turn drives the range gears. As the load is reduced, due to increased vehicle movement, the higher velocity oil flow reaches the second turbine and causes it to turn. This drives the
range gears through a higher speed combining gear. The first
turbine and its combining gear freewheel when the second turbine is operating at higher
speeds.
The result is automatic two-speed performance from the torque converter. When this is combined with two speeds in the range gearing, you get four-speed performance. Yet the operator only has two forward and one or two reverse lever positions to select.
