ProDrive™ propulsion system seamlessly shifts between two speed ranges as ground conditions change
9770 STS™ and 9870 STS Combines with ProDrive
Harvesting in rolling ground and slopes

Harvesting in rolling ground and slopes

Valuable harvest time will no longer be lost shifting on hills, on slopes, and when exiting fields to start transporting. The ProDrive propulsion system is a high-capacity feature that enables the 9770 STS and 9870 STS Combines to maintain high levels of productivity in all terrain and ground conditions.
The system uses powershift transmission technology to seamlessly shift between two speed ranges as ground conditions change, to keep the combine harvesting at the desired ground speed.
Mode one can be set for typical harvesting speeds, and mode two can be used when higher speeds are needed during harvest or when transporting the combine.
The ground speed can be infinitely varied within both modes by the operator, using the multifunction control handle on the CommandTouch™ armrest console. The multifunction handle regulates the high-capacity, variable hydrostatic pump and motor that drives the ground speed.
The productivity advantages of the ProDrive include the following:
  • Precise control of the combine speed (when going up or down hills), without the need to continuously monitor and adjust the hydrostatic control handle
  • No need to stop to shift between transmission gears
  • Automatic powershift technology between speed ranges
  • Operator-selected maximum speed within each mode, allowing for more precise control of the combine in delicate operations (for example, when hooking up headers)
  • High-capacity, high-torque ground drive performance during harvest and transport
  • No loss of ground speed when engaging rear-wheel assist (four-wheel drive, if equipped)
The ProDrive system on 70 Series STS Combines includes an integrated Harvest Smart™ feedrate control system to provide the maximum productivity and reduce operator stress and fatigue.
ProDrive basic specifications
The ProDrive hydrostatic motor has a higher displacement than that of the previous STS hydrostatic system.
Both the pump and motor are variable-displacement components that allow ProDrive to maintain high levels of torque to the ground throughout each of the two operating-speed ranges.
Compared to a three-speed transmission, the 9870 STS with ProDrive propulsion system is capable of providing 42 percent more torque at a harvesting speed of 6 mph. In similar conditions, the 9770 STS ProDrive propulsion system provides 30 percent more torque at 6 mph than the three-speed transmission.


Hydrostatic motor

Hydrostatic pump

Differential lock

Torque at 5 mph

Increase in torque at 5 mph

9870 STS

160-cm3 variable displacement

125-cm3 variable displacement


61,127 lb

171 percent

9770 STS

140-cm3 variable displacement

105-cm3 variable displacement


56,293 lb

157 percent

Three-speed transmission

105-cm3 fixed displacement

105-cm3 variable displacement


35,843 lb

100 percent

ProDrive system operation
ProDrive buttons on armrest

ProDrive buttons on armrest

ProDrive provides operators with superior control of the combine ground drive through the CommandTouch armrest console.
Using the navigation tools on the armrest, the operator can dial in the desired maximum-attainable speed within each of the two modes.
The maximum forward speed in either range can be set from 0 mph to 24 mph, but the maximum speed in range one cannot be higher than the maximum speed adjusted for range two.
CommandTouch ProDrive miles-per-hour screen

CommandTouch ProDrive miles-per-hour screen

For example, if a maximum harvest speed of 8 mph is desired and set, the full forward position of the hydrostatic control handle will deliver the speed of 8 mph.
This feature provides the operator more precise and comfortable control of the combine ground speed throughout the travel range of the hydro handle.
The adjustability of the range of speed can also make maneuvering the combine in close quarters and connecting header equipment much easier.
ProDrive in the field Click to play video
Differential lock button on armrest

Differential lock button on armrest

The ProDrive transmission available on the 9870 STS Combine features an electrohydraulic differential lock with an upgraded four-pinion differential (non-ProDrive STS combines remain with a two-pinion differential).
When operating in muddy, steep terrain or in sandy conditions that may cause one of the tires to lose traction, this differential lock will enable the operator to maintain productivity. If traction is lost, the operator can quickly and easily engage the differential lock by pressing the Diff.Lock button on the CommandTouch armrest console. An indicator light beside the button will alert the operator that the differential locking feature is engaged.
This feature eliminates the need for the operator to control the drive wheel slip manually with the independent brake pedals. When turning, the differential lock will disengage automatically if one of the brakes is applied or if the operator presses the button to disengage the differential lock.
ProDrive transmission brakes
Park brake button

Park brake button

ProDrive comes equipped with hydraulic wet-disc brakes; six brake discs per side provide ample braking performance during transport or when operating on hills.
When transporting, it is recommended the two independent brakes be locked together. When in the field mode, the brakes can be activated individually for various terrain conditions.
When the hydro handle is moved to the neutral gate, the park brake is automatically engaged to prevent unintended movement and can be locked in this mode with the touch of the park brake button on the CommandTouch armrest console.
An alarm in the CommandTouch display will alert the operator that the park brake is engaged, if it has not been released prior to hydro handle movement. When the combine engine is turned off, the park brake is automatically applied.
Base Equipment On : 9770 STS and 9870 STS Combines
Optional Equipment On : T670 Combine
Last Updated : 29-Jun-2010