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Can I Use 75W90 in My Harley Transmission?

Published by Dustin Babich on

Yes, you can use 75W90 in your Harley transmission. It is a suitable lubricant for optimal performance and protection.

When choosing a lubricant for your motorcycle’s transmission, it is important to consider the manufacturer’s recommendations and the specific needs of your bike. Using the correct viscosity can help ensure smooth gear shifting and extend the life of your transmission.

We will explore the compatibility of 75W90 and Harley transmissions, highlighting its benefits and potential drawbacks.

Additionally, we will discuss alternative lubricant options and provide tips for maintaining your Harley transmission to maximize its longevity. By the end, you will have a clear understanding of whether 75W90 is a suitable choice for your Harley transmission.

Understanding Harley Transmission Needs

Proper lubrication is essential for ensuring the optimal performance and longevity of your Harley transmission. Using the correct oil viscosity is crucial to prevent damage and maintain smooth gear shifting. Harley-Davidson recommends using 20W50 oil for most of their models, but some riders may wonder if they can use 75W90 instead.

Harley transmissions are designed with specific requirements in mind. The clutch plates and gears work together in a high-stress environment, and using the wrong oil can lead to increased wear and potential failure. While 75W90 oil may offer enhanced protection in certain applications, it is not recommended for Harley transmissions.

Using 75W90 oil instead of the specified 20W50 can result in decreased gear shifting performance, clutch slippage, and premature wear of transmission components. It is important to follow the manufacturer’s guidelines and stick to the recommended oil viscosity to ensure the proper functioning of your Harley transmission.

To summarize, it is crucial to use the appropriate oil viscosity, like 20W50, for your Harley transmission. Using 75W90 oil may lead to undesirable consequences, including decreased performance and potential damage. Always consult your owner’s manual or a trusted Harley-Davidson technician for the correct lubrication specifications.

Can I Use 75w90 In My Harley Transmission?

Using 75W90 in your Harley transmission is a common question among riders. While the manufacturer recommends specific fluids for optimal performance, it’s worth comparing the benefits and risks of alternative choices. 75W90 is a popular choice due to its wide viscosity range and ability to withstand high temperatures. It offers better lubrication and protection, especially for riders operating in extreme conditions.

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However, it’s important to note that using 75W90 may void your warranty and could potentially cause damage to your transmission if not used properly. Harley transmissions are designed with specific fluid requirements in mind, and deviating from those recommendations may affect the performance and longevity of your bike. Before making any decisions, it’s crucial to consider both the manufacturer guidelines and the potential consequences of using 75W90 in your Harley transmission.

Manufacturer Guidelines Alternative Choices
Specific fluid requirements Use 75W90 or other alternatives
Optimal performance Improved lubrication and protection
Warranty compliance Possible voiding of warranty
Longevity of transmission Potential risk of damage

Optimal Lubricants For High Performance

The right lubricant can make a significant difference in the performance and durability of your Harley transmission. High-performance lubricants are specifically formulated to meet the demands of powerful motorcycles. They offer enhanced protection and improved efficiency, ensuring smooth gear shifting and reduced wear and tear. These lubricants possess several characteristics that make them ideal for high-performance applications.

Characteristics Of High-performance Lubricants

  • Durability: High-performance lubricants are designed to withstand extreme conditions and heavy loads, providing long-lasting protection.
  • Viscosity: Viscosity plays a crucial role in lubricant selection. Optimal viscosity ensures proper lubrication, preventing friction and wear.
  • Additives: Additives such as anti-wear, anti-foam, and extreme pressure agents enhance the lubricant’s performance, reducing friction and extending component life.

When selecting an oil for your Harley transmission, consider the manufacturer’s recommendations and specifications. Look for lubricants specifically formulated for motorcycles, meeting the required viscosity and performance standards. High-performance lubricants with the right viscosity and additives will provide the necessary protection, ensuring a smooth and efficient operation of your Harley transmission.

Remember, using the correct lubricant is essential for maintaining the performance and longevity of your Harley transmission.

Maintaining Your Harley Transmission

Step-by-step guide to changing transmission fluid

Regularly changing your Harley transmission fluid is essential for optimal performance. Here is a step-by-step guide you can follow:

  1. Start by placing a drain pan below the transmission drain plug.
  2. Remove the drain plug and allow the old fluid to drain completely.
  3. Replace the drain plug and tighten it securely.
  4. Locate the transmission filler plug, usually found on the side of the transmission case.
  5. Remove the filler plug and add the recommended fluid using a funnel.
  6. Check the fluid level with the motorcycle in an upright position.
  7. If necessary, add more fluid until it reaches the correct level.
  8. Replace the filler plug and ensure it is tight.
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Checking and maintaining fluid levels will help extend the lifespan of your transmission. It is best to check the fluid level at regular intervals, preferably after every few rides or at least once a month. Pay attention to any unusual noises or gear shifting problems as it could indicate a low fluid level or other issues. By following these maintenance practices, you can enjoy a smooth and trouble-free ride on your Harley.

Frequently Asked Questions On Can I Use 75w90 In My Harley Transmission?

Can I Use 75w90 Oil In My Harley Transmission?

Yes, you can use 75W90 oil in your Harley transmission. It provides the necessary viscosity and protection for smooth gear shifting and optimal performance.

Will Using 75w90 Oil Affect My Harley’s Warranty?

No, using 75W90 oil in your Harley transmission will not void your warranty. As long as you use oil that meets the manufacturer’s specifications, your warranty remains valid.

What Are The Benefits Of Using 75w90 Oil In My Harley Transmission?

Using 75W90 oil in your Harley transmission offers several benefits, including improved gear protection, reduced friction, smoother gear shifting, and enhanced overall performance.

Can I Mix 75w90 Oil With Other Transmission Oils?

It is not recommended to mix 75W90 oil with other transmission oils in your Harley. Mixing different oils can lead to performance issues and may not provide the desired protection for your transmission. It is best to stick with one type of oil.


Using 75W90 in your Harley transmission can provide optimal performance and protection. It is important to consult your motorcycle’s owner manual and the manufacturer’s recommendations to ensure compatibility. By selecting the appropriate lubricant for your Harley transmission, you can enhance its longevity and efficiency on the road.

Make sure to conduct regular maintenance and follow the guidelines to keep your motorcycle running smoothly.

Dustin Babich
Categories: Knowledgebase

Dustin Babich

Dustin Babich

As the passionate author behind, Dustin Babich is a knowledgeable expert in all things automotive. With a deep understanding of car tools, equipment, engines, and troubleshooting techniques, Dustin Babich shares invaluable insights, practical tips, and effective solutions to empower readers in overcoming car-related challenges.

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