AMSOIL 20W-50 Synthetic Hydrostatic Transmission Fluid
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High-Zinc Hydrostatic Fluid for Zero-Turn and Stand-On Mowers
AMSOIL 20W-50 Synthetic Hydrostatic Transmission Fluid is specifically formulated to deliver smooth, responsive operation in zero-turn mowers, stand-on mowers and other equipment professionals rely on to make a living. It fights wear and viscosity loss during continuous, severe-service operation, maximizing mower speed and operability.
Unlike motor oils, AMSOIL Synthetic Hydrostatic Transmission Fluid is purpose-built to withstand the unique demands of hydrostatic transmissions. It lasts up to 2X original equipment manufacturer (OEM) recommendations, helping professionals save money and reduce downtime.
Key Benefits
- Fights wear for smooth, responsive operation
- Purpose-built to outperform motor oils in hydrostatic transmissions
- Resists high heat and shear — naturally tough synthetic base oils
- High levels of zinc-based anti-wear additives maintain tight wheel-motor tolerances
- Maximizes mower speed and responsiveness for increased productivity
- Lasts up to 2X OEM-recommended service intervals
- Naturally heat-resistant base oils reduce deposits and keep equipment clean
- Warranty Secure — keeps factory equipment warranty intact
Maximizes Mower Speed, Resists Heat and Shear
Maximizes mower speed and responsiveness: In many zero-turn mowers, oil pressure drives the wheel motors. AMSOIL Synthetic Hydrostatic Transmission Fluid contains high levels of zinc-based anti-wear additives to help maintain the tight tolerances in wheel motors, while its synthetic base oils naturally resist viscosity loss in extreme heat.
Commercial-grade wear protection: Naturally tough synthetic base oils resist viscosity loss due to shear and high heat, promoting the formation of a durable sacrificial anti-wear film on components that helps extend mower life.
Maintains cleanliness: Hydrostatic transmission temperatures can exceed 230°F (110°C). Naturally heat-resistant synthetic base oils reduce deposits and help keep equipment clean and running properly season after season.
Technical Specifications
| Property | Value |
|---|---|
| Kinematic Viscosity @ 100°C, cSt | 17.2 |
| Kinematic Viscosity @ 40°C, cSt | 137.3 |
| Viscosity Index | 137 |
| CCS Viscosity | 6197 cP @ -15°C |
| Pour Point | -36°C (-33°F) |
| Flash Point | 242°C (468°F) |
| Fire Point | 258°C (496°F) |
| Four-Ball Wear Test (@ 40 kg, 75°C, 1200 rpm, 1 hr), Scar, mm | 0.42 |
Industry Certifications & OEM Approvals
API
- SM, SL, SJ, SH, SG (applications)
Applications
Use in hydrostatic transmissions that require 15W-50 or 20W-50 oil recommended for API SM, SL, SJ, SH or SG, including (not limited to) those found in zero-turn, riding and stand-on mowers made by SCAG, Toro, Ferris, Snapper Pro, Gravely, Ariens, Exmark, Walker, Hustler, Wright, Dixie Chopper, John Deere, Husqvarna, EverRide, Bad Boy and Cub Cadet. Not for use in engines.
Pros and Cons
Pros
- Fights wear for smooth, responsive operation
- Purpose-built to outperform motor oils in hydrostatic transmissions
- Resists high heat and shear — naturally tough synthetic base oils
- High levels of zinc-based anti-wear additives maintain tight wheel-motor tolerances
- Maximizes mower speed and responsiveness for increased productivity
- Lasts up to 2X OEM-recommended service intervals
- Naturally heat-resistant base oils reduce deposits and keep equipment clean
- Warranty Secure — keeps factory equipment warranty intact
Cons
- Premium Investment: Higher initial cost compared to conventional or "shelf-brand" synthetic oils.
- Limited Local Retail: Primarily available through authorized dealers and specialized synthetic outlets. National Synthetics is a local stocking dealer. Call 1-678-944-8816 to confirm in-stock items for same-day local pickup.
Order Through Your Independent AMSOIL Dealer
Keep your crew's mowers fast and responsive all season. As your Independent AMSOIL Dealer, we provide expert guidance and competitive pricing on all AMSOIL products.
Independent AMSOIL Dealer #1858536
Shipping & Returns
Fast, Reliable Shipping
- Free standard ground shipping on orders of $100 ($130 in Canada) or more.
- Orders under the threshold ship for a flat $9.99 ($12.99 in Canada) freight charge.
- In-stock items typically delivered in two to three business days.
- U.S. and Canada only — no shipments to PO Boxes.
30-Day Return Policy
- Return unopened, currently marketed products within 30 days for a full refund (minus freight).
- Exchange unopened products within 90 days with no restocking fee.
- Special-order items are non-returnable.
- Returns are handled directly by AMSOIL.
Frequently Asked Questions
It is purpose-built for hydrostatic transmissions in zero-turn, riding and stand-on mowers that require 15W-50 or 20W-50 oil recommended for API SM, SL, SJ, SH or SG — including equipment from SCAG, Toro, Ferris, Snapper Pro, Gravely, Ariens, Exmark, Walker, Hustler, Wright, Dixie Chopper, John Deere, Husqvarna, EverRide, Bad Boy and Cub Cadet. It is not for use in engines.
Unlike motor oils, AMSOIL Synthetic Hydrostatic Transmission Fluid is purpose-built to withstand the unique demands of hydrostatic transmissions. Its high-zinc anti-wear additives maintain the tight tolerances in wheel motors and its synthetic base oils resist viscosity loss due to shear and high heat — both critical to preserving mower speed and responsiveness.
AMSOIL 20W-50 Synthetic Hydrostatic Transmission Fluid delivers excellent protection for 2X the original equipment manufacturer (OEM) recommended service interval, helping professionals save money and reduce downtime.
No. AMSOIL 20W-50 Synthetic Hydrostatic Transmission Fluid is Warranty Secure, keeping your factory warranty intact. It is a high-performance replacement for vehicle-manufacturer-branded products and is backed by the AMSOIL Limited Warranty.
Customer Reviews
See all 58 reviewsZero Turn hydro oil
Excellent Hydro OiI !! After changing to this oil my zero turn mowers hydro pumps run quieter and smoother than ever! I have an Exmark Lazer that has 2500 hours on the pumps!! This oil has made that many hours on my original hydro gear pumps possible! Thanks Amsoil!! Steven
Verified customer review via AMSOIL.com.
Definitely an upgrade
Far superior lubrication. Hydro drives run smoother, cooler and cleaner than with any other 20W-50 oil I have used. I mow 2 acres 1-2 times per week on hills. Creates a lot of heat in the oil. My expansion tanks show much cleaner oil. The drives are quieter than they were before. What else can I say? Great product.
Verified customer review via AMSOIL.com.
Independent AMSOIL Dealer #1858536. Product information sourced from AMSOIL. Visit AMSOIL.com for the most current product details and availability.