Sundstrand HydraulicsAbout Sundstrand Hydraulics and Products

Greatly increased productivity and reliability are the key benefits that Sundstrand hydraulics transmissions bring to Agriculture, Construction Machinery, Industrial and Material Handling Applications.

Simplicity. No clutch is required- no gear changing during operation. A single lever control provides infinitely variable forward and reverse speeds and dynamic braking. Rapid reversals of direction can be made without damage to the drive.

Operation is almost effortless. Response is immediate and positive. Even unskilled personnel can master operation in a very short time.

Maneuverability is greatly improved over conventional systems. Greatly increased loads can be moved from a standing start, and there is no surge or speed change when loads are suddenly released. Constant ground speeds can be maintained.

Speeds can be varied “on the go” while working mechanism is independently operated at its most efficient speed. The prime mover also can be run at optimum speeds regardless of mechanism speed. In short, a totally new and almost limitless control of all functions is achieved for maximum vehicle efficiency.

Reports from users are universal in emphasizing dramatically increased productivity, ease of handling, and elimination of major maintenance problems.



Sundstrand hydraulics transmissions have been expressly designed to provide the long life and reliability required in work related applications. Extended fatigue life, minimum deflection of parts, and adequate reserve capacity to absorb shock loads are the features that keep machines on the job.

The hydrostatic transmission offers infinite control of speed and direction. The operator has complete control of speed and direction. The operator has complete control of the system with one lever for starting, stopping, forward motion, or reverse motion. The dynamic braking capabilities inherent with the closed circuit hydrostatic transmission may provide normal braking requirements. This capability is dependent upon the transmission size, including relief valve settings, as well as the retarding characteristics of the prime mover. Stopping time will be related to the momentum of the mechanism. When negotiating downgrades at top speed , there is a greater probability that the prime runaway condition could result. Negotiating such a downgrade can be safely accomplished at lower speeds. In any event, the inherent braking capabilities of the transmission should not be construed as a substitute for service brakes.


Control of the variable displacement, axial piston pump is the key to controlling the vehicle. Prime mover horsepower is transmitted to the pump. When the operator moves the control lever, the swashplate in the pump is tilted from neutral. The position of the control lever will determine the angle of the swashplate and, therefore, the volume of oil displaced by the pump. The control lever is seedless, therefore, the direction and speed of the vehicle is infinitely variable from zero to maximum.

Pumps and motors are contained in separate housings or may be connected by a common end cap. All valves required for a closed loop circuit are included in either the pump or motor assemblies. A reservoir, filter, cooler, and lines complete the circuit.