Hydrostatic Transmission Fluids
AMSOIL synthetic hydrostatic transmission fluids are engineered to protect the pumps, motors and other components used in hydrostatic drive systems. Advanced synthetic formulations provide excellent wear protection and maintain dependable performance under the high temperatures and demanding operating conditions commonly encountered by zero-turn mowers and other hydrostatic equipment.
Browse AMSOIL hydrostatic transmission fluids below for high-performance lubrication designed to help protect hydrostatic drive systems and maintain smooth, reliable equipment operation.
AMSOIL Hydrostatic Transmission Fluids
Hydrostatic transmissions use hydraulic pressure to transfer engine power into controlled mechanical movement. Common in zero-turn mowers and other outdoor power equipment, these systems combine the demands of a hydraulic system with the continuous load, heat and wear associated with a power-transmission application.
AMSOIL hydrostatic transmission fluids are formulated to provide dependable hydraulic performance while protecting pumps, motors, gears and other drivetrain components under demanding operating conditions.
How a Hydrostatic Transmission Works
Rather than using a conventional mechanical gearbox with a fixed series of gear ratios, a hydrostatic transmission typically uses an engine-driven hydraulic pump to supply pressurised fluid to a hydraulic motor. Varying the direction and volume of fluid flow allows the transmission to provide smooth, continuously variable control of vehicle speed and direction.
The fluid is therefore an active part of the power-transmission system. It must transmit hydraulic pressure efficiently while simultaneously lubricating and protecting highly loaded internal components.
Heat Is a Major Challenge
Hydrostatic transmissions can generate substantial heat, particularly during prolonged operation, heavy workloads and low-speed manoeuvring. Commercial mowing and demanding property-maintenance applications may keep the transmission working continuously for hours at a time, often during hot Australian conditions.
As lubricant temperature rises, maintaining appropriate viscosity and resistance to oxidation becomes increasingly important. A quality synthetic hydrostatic transmission fluid helps maintain a protective lubricating film while resisting viscosity loss, deposits and lubricant degradation during demanding service.
Why Use a Purpose-Built Hydrostatic Transmission Fluid?
A hydrostatic transmission may look like a hydraulic system, but that does not mean any general-purpose hydraulic oil is automatically suitable. Hydrostatic drives can place specialised requirements on fluid viscosity, wear protection, oxidation resistance, hydraulic performance and compatibility with the transmission design.
Likewise, engine oil, automatic transmission fluid and hydraulic fluid should not be substituted solely because they appear to have a similar viscosity. Always follow the equipment or transmission manufacturer's lubricant requirements and select a product suitable for the particular hydrostatic system.
Zero-Turn Mower Transmission Fluid
Zero-turn mowers place particularly high demands on their hydrostatic drives. Independent drive systems repeatedly change speed and direction as the mower turns, accelerates and manoeuvres, while commercial and large-property applications can involve extended periods of continuous operation.
AMSOIL 20W-50 Synthetic Hydrostatic Transmission Fluid is specifically formulated for zero-turn and other hydrostatic transmission applications requiring an appropriate 20W-50 lubricant. It provides synthetic protection for hard-working hydrostatic systems while helping maintain consistent transmission performance under heat and load.
Don't Forget Hydrostatic Transmission Maintenance
Hydrostatic transmissions are sometimes treated as maintenance-free components, but service requirements vary between equipment and transmission manufacturers. Serviceable systems may require periodic fluid and filter changes, and correct fluid level is essential for proper hydraulic operation.
Follow the equipment manufacturer's service procedure and interval, particularly for commercial machines and equipment subjected to extended or severe use. Where a transmission has separate filters, reservoirs or specific filling and purging procedures, these requirements should also be followed when servicing the system.
Find the Correct AMSOIL Product
Check the equipment or transmission manufacturer's required viscosity and lubricant specification before selecting a hydrostatic transmission fluid. Browse AMSOIL hydrostatic transmission products for zero-turn mowers and other compatible outdoor power equipment, or use the AMSOIL Product Finder where application information is available.
