How to Change the Transmission Oil on a Harley-Davidson Bike


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How To Change The Transmission Oil On A Harley Davidson

Are you a Harley-Davidson biker, and you are looking to find out how to change the transmission oil in your bike? If yes, then you are certainly in the right place.

Changing the transmission oil on a Harley-Davidson bike is quite easy if you know the right steps. Changing the transmission oil on your bike involves locating the transmission drain plug, removing the drain plug, cleaning the drain plug, sliding the new O-ring onto the transmission plug, and reinstalling the drain plug. Further, you need to remove the transmission cover and dipstick. Make use of a long-necked funnel for installing the transmission oil. However, you should make sure that you don’t overfill the transmission.

In this article, you will get to learn all about changing transmission oil, how to change the transmission oil on a Harley-Davidson bike, difference between transmission, primary, and engine oil, and more. Stick around to get all the answers that you are looking for.

Transmission Oil on Harley-Davidson Bikes

If you go through motorcycle maintenance forums, you will find the topic of transmission oil to be a cause of controversy. New bikers are often surprised to know that the transmission uses the same oil as the engine. The good news for you is that for most bikers, once you have changed the engine oil, you would need to change the transmission too.

Exceptions to this rule come in the shape of classic bikes from brands like Buell, Triumph, and Harley-Davidson. These motorcycles are commonly of a pre-unit construction, which means that their transmissions also require regular oil changes.

Synthetic V-Twin Transmission Fluid comes with a higher viscosity compared to other types of oil like 20W-50 Synthetic V-Twin Motorcycle Oil. A thicker or higher-viscosity lubricant helps keep noisy transmission gears and enables smooth shifts. The lubricant will develop a slightly thicker fluid film on gears, providing cushion to help diminish loud sound and gear noise.

It will be good to warm up your motorcycle a little before you start the transmission oil change, as warm oil can drain out of the transmission more effectively. Once you have done that, you need to park your bike on level ground using a paddock stand or center stand.

You will need to locate the oil drain plug, which will be under the bike and between the shock absorbers, before placing the oil drain tray underneath. While the oil is draining in the drain tray, it’ll be a suitable option to wipe off the drain plug with a rag before you put it somewhere else as the built-in magnet will probably have a small number of metal filings attached, and you won’t need to re-introduce them to the transmission.

As the old oil has drained away, you need to smear some oil on the O ring, replace the drain plug, and then tighten it with a torque wrench. The setting for this is about 15–17 pounds, but you must check with your Harley’s owner’s manual to make sure you get it right.

Upon changing the transmission oil, you should also ensure that there is no leakage from the fill or drain hole. Remember to check once again after riding to make sure that the transmission maintains the right level of oil.

How to Change the Transmission Oil on a Harley-Davidson Bike

The transmission system on your Harley-Davidson bike will be located on the engine block under the engine cover. Changing the transmission oil should be a part of scheduled maintenance that occurs once every 50,000 to 60,000 miles or 3 years, whichever comes first. Fresh transmission oil can prevent the gears from grinding and the engine from overheating.

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For better shift performance and maximum wear protection, it’ll be important that you periodically change the transmission oil in your Harley-Davidson bike. Otherwise, the fluid could break down and struggle to protect gears and bearings, not to mention interfere with the crisp shifts that you’re looking for when riding. Here are the steps on how to change the transmission oil on a Harley-Davidson bike – 

Step 1: Gather the tools

Neglecting transmission oil change could lead to costly engine damage. Fortunately, changing the transmission oil will require a few tools and just a few minutes of time. Here are the tools that you will need –

  • Drain pan
  • 5/8-inch socket with a socket wrench 
  • 3-inch extension 
  • Torque wrench 
  • Funnel
  • 3/8-inch ball-end Allen wrench 
  • New drain-plug O-ring
  • V-Twin Transmission Fluid 

Step 2: Locate the transmission drain plug

First, you need to locate the transmission drain plug. This can be quite tricky. You will need to look for the two shock absorbers. The drain plug will be located between the shock absorbers, under the transmission.

Step 3: Remove it

You should make use of a ratchet, a 3-inch extension, and a 5/8-inch socket for removing it. Once it is loose, you have to use your hands to finish removing the drain plug and prevent it from falling into the drain pan.

Step 4: Drain old oil and clean the drain plug

While the transmission oil is draining, you have to clean the drain plug. Make sure that you are removing all the debris and check the drain plug for any damage.

Step 5: Install a new O-ring

Now, you should slide the new O-ring onto the transmission plug before running it all the way to the bottom. Now, re-install the drain plug. Initially, snug it manually and use the torque wrench set at 14-21 foot-pounds torque for tightening it.

Step 6: Remove the transmission cover and dipstick

Make use of a 3/8-inch ball-end Allen wrench for removing the transmission cover and dipstick. Use a long-necked funnel for installing the transmission fluid. 

Step 7: Add fresh oil

You are now ready to add fresh transmission oil specified by the OEM. Add the oil slowly and carefully using the funnel. Once it is done, you should replace the filler cap via the torque wrench, wipe away any excess oil that might have spilled or splashed, and you’ll be ready to ride again.

Be careful that you don’t overfill the transmission. Check the owner’s manual for the correct fluid capacity. Make sure that you stop and check the site gauge on the bottle so that you can prevent adding excess fluid.

Step 8: Verify the fluid level

Some Harley models require checking the transmission fluid when the bike is on the kickstand. Check the owner’s manual for specific instructions for your motorcycle, then pull out the dipstick and verify the transmission fluid level. To finish things off, you should make sure that you dispose of the used transmission oil properly.

Can You Use the Same Oil for Transmission, Motor, and Primary?

Some V-Twin motorcycles like Victory and Indian motorcycles used a shared sump, which means that they use the same lubricant in the transmission, engine, and primary chain case. However, most Harley-Davidson bikes use a separate sump for each lubricant. This presents Harley-Davidson bike owners with a complicated choice – should they use the same lubricant in all three areas of the motorcycle, or use a separate lubricant for each area? 

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Lubricant Oil For Harley-Davidson

Often, the 20W-50 Synthetic V-Twin Motorcycle Oil is recommended on most Harley-Davidson bikes for the engine, primary chain case, and transmission. Using the same oil for transmission, motor, and primary will give you benefits like –

  • Convenience – If the biker buys and installs one lubricant, it’ll reduce the cost while resulting in fewer half-used oil bottles lying around 
  • Simplicity – Remembering to purchase one lubricant will be easier than having to remember three lubricants
  • Great all-around performance – Using the same lubricant in all three areas of the bike will deliver amazing all-around performance 

The 20W-50 Synthetic V-Twin Motorcycle Oil is formulated as an amazing all-around lubricant. It is capable of delivering outstanding engine protection because of its proven ability to fight wear, maintain cleanliness, reduce heat, and prevent corrosion during storage.

Synthetic V-Twin Motorcycle Oil will also feature a shear-stable formulation. It will resist viscosity loss despite the pressure and churning action of high RPM transmission gears, which allows it to deliver reliable transmission protection. Synthetic V-Twin Motorcycle Oil complies with JASO MA/MA2 standards and is wet-clutch compatible for tremendous performance in not just transmission but engine and primary chain case too. Its fictional properties come dialed in to allow the clutch plates to engage and disengage without having to load or slip for smooth shifts.

Despite numerous benefits, some bikers continue to question the practice of using one oil in all three areas of their motorcycles. They have a hard time accepting that motor oil could protect the transmission and primary chain case too.

How to Dispose Used Transmission Oil

While most bikers pay someone to change the transmission oil, there is still a huge chunk of bikers who crawl under their bikes and do it themselves. Once you are done, what should you do with the used transmission oil? 

According to the Environmental Protection Agency, used oil from a single oil change could easily contaminate 1 million gallons of fresh water. This equates to almost a year’s supply for 50 people. Just one quart of used oil is enough to produce a 2-acre slick. 

Here is all that you need to know for disposing of used transmission oil.

Take used oil to an Auto Parts Store or Quick Lube

Many businesses that sell or change oil accept it for recycling free of charge. For instance, most AutoZone and Advanced Auto Parts stores accept used motor oil and transmission oil. Likewise, numerous Jiffy Lube stores are designated oil recycling collection centers. You must call the businesses in your area for ensuring that they will take your used oil.

You can do the businesses a favor and make sure that the used transmission oil is stored properly in clean plastic containers. It is convenient to use your empty oil bottles as storage containers for used transmission oil.

You must avoid mixing used oil with antifreeze. Some collection centers will not take motor or transmission oil that is mixed with antifreeze.

You shouldn’t forget the oil filter, though. Most collection centers recycle used oil filters as well. In fact, since used oil from discarded oil filters can easily leak into the soil and water, many local and state governments have banned their disposal in area landfills. Like used motor oils, used oil filters will be highly recyclable, and the steel could be used for manufacturing a wide variety of new products like appliances, construction materials, and vehicles.

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How to Recycle Transmission Oil Bottles

You can also recycle your motor oil and transmission oil bottles instead of tossing them in the trash. If not disposed of properly, those bottles could end up in a landfill. The empty bottles contain residual oil, which could end up contaminating groundwater.

Many businesses that accept used transmission oil will also accept empty motor oil bottles. It would be the easiest option to pour the used oil into empty bottles and then dispose of both at the same time.

Typically, municipal recycling facilities also recycle transmission oil bottles. However, the disposal will vary from city to city, so you need to call them ahead of time to be sure.

What Happens to Used Transmission Oil After Recycling?

Used transmission oil or motor oil can be used for powering industrial plant boilers or other heating applications.

In fact, merely recycling 2 gallons of waste oil is enough to generate enough electricity to run an average household for almost 24 hours. It can even be distilled into diesel or marine fuel.

Used oil can also be re-defined and used for making new oil. Refiners can restore the lubricating qualities of base oils, remove any contaminants, and introduce new additives for creating a whole new product.

Create Less Waste Oil to Begin With

The best way to deal with used transmission oil would be to use as little as possible. The oil market today contains multiple oil options that are recommended for extended drain intervals. Some of them will allow you to go an entire year between oil changes.

If all the Harley-Davidson bikes in the United States use high-quality synthetic motor oil for extended drain intervals, it is possible to eliminate billions of gallons of used oil. 

Not only that, but changing oil less often will also reduce packaging waste, not to mention saving the time that you’d have spent changing oil. Regardless of how often you have to change oil, ensure that your used oil disposal plan does not include burying it in your yard.


How often should I change the transmission fluid in my Harley-Davidson bike?

It is recommended that you should change the oil at 1,000 miles and then every 10,000 miles after that. Harley-Davidson recommends that you should use 20W-50 oil.

How much oil goes into a Harley-Davidson bike’s transmission?

The transmission fluid capacity of a Harley-Davidson bike is approximately 24 ounces (0.71 liters). You need to inspect the O-ring for tears or damage. You can also replace if it needed. Wipe off any foreign material from the drain plug.

Would it be possible to change the transmission oil myself?

A transmission flush-and-fill from a dealer can cost you anywhere between $149 and $199. If you try doing it yourself, you will be able to save almost $100. Draining the old fluid can be a messy, ugly job. This is the case because you will have to lie under your bike, drop the pan, and get drenched in the fluid.

What kind of oil goes in a Harley-Davidson bike’s transmission?

It is recommended that you should put 20W-50 Synthetic V-Twin Motorcycle Oil in the transmission, engine, and primary chain case on most Harley-Davidson bikes.

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