About this item

• Product Overview

  Synthetic, high-zinc formula fights wear. Built for hydrostatic transmissions to maintain mower speed and efficiency better than motor oil. Promotes long transmission life for professionals who depend on their equipment to make a living.

  See the product data sheet for full details.

  MAXIMIZES MOWER SPEED & RESPONSIVENESS

  • Zinc-based additives fight wear to maintain motor-wheel tolerances and proper oil pressure.
  • Resists viscosity loss in extreme heat for maximum mower speed and responsiveness.

  COMMERCIAL-GRADE WEAR PROTECTION

  • Forms a thick, durable film on gear teeth and other components to guard against metal-to-metal contact and wear.
  • Resists mechanical shear and viscosity loss for excellent wear protection and long transmission life.
  • Maintains protective viscosity despite extreme heat to ensure strong protection.

  MAINTAINS CLEANLINESS

  • Naturally heat-resistant synthetic base oils help reduce deposits.
  • Promotes component cleanliness for peak efficiency and excellent performance season after season.

  See the product data sheet for full details.

  *All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use.

• Technical Specifications
  Data Bulletin

  Data Bulletins

  Warranty

  WARRANTY

  SDS

  SDS

  SDS (French)

  
  
  
• Product Reviews
  5 star rating

  Based on 52 reviews

  Based on 52 reviews

  See all customer reviews

  Sort by

  Most Recent Most Helpful Highest Rating Lowest Rating Oldest

  • 5 star rating
    John Deere hydrostatic transmission service
    By  CARL,  a  Verified Buyer  from  Ohio  on  June 01, 2026

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    Used the Amzoil 20w50 synthetic oil to service transmission on John Deere D125 with 270 hours on it. A bit of wining before service. The 20w50 works great, no wining and lawn tractor runs great!
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Definitely an upgrade
    By  Jim,  a  Verified Buyer  from  Kentucky  on  May 27, 2026

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    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.
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Zero turn transmission oil
    By  WILLIAM,  a  Verified Buyer  from  Florida   on  May 03, 2026

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    Works great. It gets very hot here. Have a 54 inch deck. Run machine pretty well long hours.
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Fixed the shudder in my Gravely ProStance—best decision I’ve
    By  KEEGAN,  a  Verified Buyer  from  Houston, Texas  on  May 01, 2026

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    I’ve been fighting a persistent shudder in the hydros of my Gravely ProStance 36 for over a year, and it was driving me to the point of considering a full hydro replacement. I tried everything: multiple different high-end fluids, constant air purges, and frequent filter changes. Nothing worked for long. It would always run great after an oil change, but as soon as the fluid began to shear, that dreaded shudder would return—and was always present by the second mow. Dealing with the intense Texas heat, I decided to try the AMSOIL 20W-50 Synthetic Hydrostatic Transmission Fluid as a last-ditch effort before biting the bullet on new hydros. The difference is night and day. The shudder is completely gone. I’m now 10 mows in, and even in this heat, the performance is just as smooth as the day I poured it in. It honestly feels like a brand-new mower again. If you’re dealing with heat-related shearing or jerky performance, don’t waste your time with other fluids. I am someone who never takes the time to review products, so the fact that I’m writing this speaks volumes to the quality of this fluid. I only wish I had made the switch to AMSOIL sooner—it saved me from a massive repair bill and a lot of frustration. I’m now in the process of switching all my engines over to AMSOIL products as well. Highly recommended.
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great stuff
    By  JASON,  a  Verified Buyer  from  WV  on  April 23, 2026

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    AMSOIL brought my John Deere z425 back to life! The transmission would get hot and I couldn’t finish mowing, changed the oil with this stuff and I can mow all day!
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Great For Use In Exmark Walkbehinds
    By  KEVIN,  a  Verified Buyer  from  Michigan  on  January 13, 2026

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    Have used Amsoil 20w50 in Exmark Walk behind Hydro's since Mobil 1 removed zinc. The Amsoil has one of the highest zinc contents available in a 20w50, which is why we chose it. Have 10 units over 4,000 hours on original hydro's and 2 over 5,000 hours on original hydro's. Maintenance and Quality of oil have to be the reason.
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  • 5 star rating
    good product
    By  JOSE,  a  Verified Buyer  on  December 22, 2025

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    good for zt3100 transgear
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Definitely an improvement
    By  PETER,  a  Verified Buyer  from  Spencer   on  September 05, 2025

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    It definitely revived a JD x300 tuff torque transmission and refreshed a JD 757 Ztrack
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    20-50
    By  MATTHEW,  a  Verified Buyer  on  July 06, 2025

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    Great oil. Never use any other brand. Thanks AMSOIL
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  • 5 star rating
    Noticeable Improvement
    By  JOHN,  a  Verified Buyer  from  Shannon, Georgia  on  June 27, 2025

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    My zero turn had 1000 hrs and one side was significantly less powerful than the other and would not back up on an incline. I had to remove the units to drain the original oil as they were not designed for oil changes. I drained them and added Amsoil and it breathed new life into both sides after only a few minutes of driving. One side is still stronger than the other but both work significantly better and I’m hoping to get several more mowing seasons out of them now. I will be using this in all future zero turns and recommending it to my friends.
    Bottom Line

    Yes, I would recommend this to a friend.
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• Highlights

  • Fights wear for smooth, responsive operation
  • Purpose-built to outperform motor oils
  • Resists high heat and shear
• Returns

  We offer easy returns for customers. If your product is unused and unopened, you may return it within 30 days for a full refund of the purchase price. View full AMSOIL Return Policy.

• Payments

  We accept Visa, Mastercard, American Express, Discover and PayPal, and provide secure checkout and encrypted payment processing.

• Product Overview

  Synthetic, high-zinc formula fights wear. Built for hydrostatic transmissions to maintain mower speed and efficiency better than motor oil. Promotes long transmission life for professionals who depend on their equipment to make a living.

  See the product data sheet for full details.

  MAXIMIZES MOWER SPEED & RESPONSIVENESS

  • Zinc-based additives fight wear to maintain motor-wheel tolerances and proper oil pressure.
  • Resists viscosity loss in extreme heat for maximum mower speed and responsiveness.

  COMMERCIAL-GRADE WEAR PROTECTION

  • Forms a thick, durable film on gear teeth and other components to guard against metal-to-metal contact and wear.
  • Resists mechanical shear and viscosity loss for excellent wear protection and long transmission life.
  • Maintains protective viscosity despite extreme heat to ensure strong protection.

  MAINTAINS CLEANLINESS

  • Naturally heat-resistant synthetic base oils help reduce deposits.
  • Promotes component cleanliness for peak efficiency and excellent performance season after season.

  See the product data sheet for full details.

  *All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use.

• Technical Specifications
  Data Bulletin

  Data Bulletins

  Warranty

  WARRANTY

  SDS

  SDS

  SDS (French)

  
  
  
• Product Reviews
  5 star rating

  Based on 52 reviews

  Based on 52 reviews

  See all customer reviews

  Sort by

  Most Recent Most Helpful Highest Rating Lowest Rating Oldest

  • 5 star rating
    John Deere hydrostatic transmission service
    By  CARL,  a  Verified Buyer  from  Ohio  on  June 01, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Used the Amzoil 20w50 synthetic oil to service transmission on John Deere D125 with 270 hours on it. A bit of wining before service. The 20w50 works great, no wining and lawn tractor runs great!
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Definitely an upgrade
    By  Jim,  a  Verified Buyer  from  Kentucky  on  May 27, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    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.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Zero turn transmission oil
    By  WILLIAM,  a  Verified Buyer  from  Florida   on  May 03, 2026

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    Describe the issue

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    Works great. It gets very hot here. Have a 54 inch deck. Run machine pretty well long hours.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Fixed the shudder in my Gravely ProStance—best decision I’ve
    By  KEEGAN,  a  Verified Buyer  from  Houston, Texas  on  May 01, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    I’ve been fighting a persistent shudder in the hydros of my Gravely ProStance 36 for over a year, and it was driving me to the point of considering a full hydro replacement. I tried everything: multiple different high-end fluids, constant air purges, and frequent filter changes. Nothing worked for long. It would always run great after an oil change, but as soon as the fluid began to shear, that dreaded shudder would return—and was always present by the second mow. Dealing with the intense Texas heat, I decided to try the AMSOIL 20W-50 Synthetic Hydrostatic Transmission Fluid as a last-ditch effort before biting the bullet on new hydros. The difference is night and day. The shudder is completely gone. I’m now 10 mows in, and even in this heat, the performance is just as smooth as the day I poured it in. It honestly feels like a brand-new mower again. If you’re dealing with heat-related shearing or jerky performance, don’t waste your time with other fluids. I am someone who never takes the time to review products, so the fact that I’m writing this speaks volumes to the quality of this fluid. I only wish I had made the switch to AMSOIL sooner—it saved me from a massive repair bill and a lot of frustration. I’m now in the process of switching all my engines over to AMSOIL products as well. Highly recommended.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Great stuff
    By  JASON,  a  Verified Buyer  from  WV  on  April 23, 2026

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    Describe the issue

    Failed to verify captcha

    Cancel Submit
    AMSOIL brought my John Deere z425 back to life! The transmission would get hot and I couldn’t finish mowing, changed the oil with this stuff and I can mow all day!
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Great For Use In Exmark Walkbehinds
    By  KEVIN,  a  Verified Buyer  from  Michigan  on  January 13, 2026

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    Have used Amsoil 20w50 in Exmark Walk behind Hydro's since Mobil 1 removed zinc. The Amsoil has one of the highest zinc contents available in a 20w50, which is why we chose it. Have 10 units over 4,000 hours on original hydro's and 2 over 5,000 hours on original hydro's. Maintenance and Quality of oil have to be the reason.
    Was this review helpful?

    YES (3) NO (0)
  • 5 star rating
    good product
    By  JOSE,  a  Verified Buyer  on  December 22, 2025

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    good for zt3100 transgear
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (0)
  • 5 star rating
    Definitely an improvement
    By  PETER,  a  Verified Buyer  from  Spencer   on  September 05, 2025

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    Describe the issue

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    It definitely revived a JD x300 tuff torque transmission and refreshed a JD 757 Ztrack
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (2) NO (0)
  • 5 star rating
    20-50
    By  MATTHEW,  a  Verified Buyer  on  July 06, 2025

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    Great oil. Never use any other brand. Thanks AMSOIL
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  • 5 star rating
    Noticeable Improvement
    By  JOHN,  a  Verified Buyer  from  Shannon, Georgia  on  June 27, 2025

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    My zero turn had 1000 hrs and one side was significantly less powerful than the other and would not back up on an incline. I had to remove the units to drain the original oil as they were not designed for oil changes. I drained them and added Amsoil and it breathed new life into both sides after only a few minutes of driving. One side is still stronger than the other but both work significantly better and I’m hoping to get several more mowing seasons out of them now. I will be using this in all future zero turns and recommending it to my friends.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (3) NO (0)