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How to Change the Transmission Hydraulic Oil in Your YT235 Tractor


Extend the life of your YT235 tractor by performing a transmission hydraulic oil and filter change according to your owner’s manual recommendation. For this tractor series, that means performing transmission hydraulic oil change after the first 50 hours of operation, then again at 300 hours, and every 300 hours after that.   

Let’s get started. 

What You Need to Perform a Transmission Hydraulic Oil Change 

Here’s everything you need to perform the transmission hydraulic oil change on your YT235 tractor.  

  • 17 mm Socket and Ratchet, or Wrench. These tools will help you access your oil filter.   
  • Oil Filter Wrench or Strap Wrench. To remove the filter, have these tools at hand. 
  • Clean Shop Rags and Absorbent Pads. You’ll be wiping clean several tractor components, so be sure to keep clean rags handy. Pads are good to have in case of spills.
  • Safety Glasses and Nitrile Gloves. Transmission oil can harm your skin and irritate your eyes, so equip your safety gear before starting.   
  • Wheel Chocks. Keep your tractor steady throughout the transmission oil change by securing your wheel chocks. 
  • 8.2 Gallons of T500A Hydraulic Fluid. Your transmission is a hungry beast. Ensure you have 9 gallons of the appropriate fluid ready to replace the old. 
  • Line Filter. The part number for the line filter is 1A7180-48210. 
  • Hydraulic filter. The part number on the right hydraulic filter is 198119-48310. 
  • Oil Drain Pan. Get an oil drain pan with enough capacity for at least 9 gallons of oil.  
  • Funnel. Using a funnel will keep spillage to a minimum.  

How to Perform a Transmission Hydraulic Oil Change 

Start by moving your tractor onto a level surface, such as a concrete pad or driveway. 

  1. Warm Up the Oil. Once your tractor is in position, keep the engine running long enough to warm up the transmission hydraulic oil. After a few minutes, lower all attachments and shut off the engine. Position the wheel chocks behind the tires to help keep the tractor from rolling or moving. 
  2. Allow Oil to Cool and Position Oil Pan. Allow the oil to cool. When you start the oil change, the oil should be warm but not hot enough to cause burns. Position the oil pan under the transmission drain plug. 
  3. Remove Transmission Oil Drain Plug and Filler Cap. Place the oil pan underneath the transmission drain plug.  Using your 17mm socket and ratchet or wrench, remove the transmission drain plug. To speed up the draining process, remove the filler cap as well. Ensure that you clean around the filler cap with a shop rag to prevent debris from entering the hydraulic system. 
  4. Allow the Oil to Drain. Once the plug is open, allow the oil drain completely. Use rags and absorbent pads to clean any spilled oil. 
  5. Replace the Transmission Oil Drain Plug. When the oil has drained, replace the transmission oil drain plug. Then, clean the area around the plug. This will remove any residual oil. 
  6. Remove the Hydraulic Filter. Your hydraulic filter is located under and behind the left rear wheel of your tractor. Remove the hydraulic filter using a filter or strap wrench. Check the base of the hydraulic filter and to make sure the gasket from the previous filter has been removed. 
  7. Install the New Hydraulic Filter. To install a new hydraulic filter, fill the filter to between one-third and one-half full with hydraulic oil. Apply a small amount  of clean transmission hydraulic oil onto the gasket. Wipe the filter base and install the new filter, turning clockwise until the gasket is seated. Use a filter or strap wrench to turn the filter an additional one half turn.
  8. Remove the Line Filter. Next, locate the line filter under the tractor (near the loader connections) and remove the line filter using a filter or strap wrench.  
  9. Install New Line Filter. To install a new line filter, fill the new filter to between one third and one half full with hydraulic oil. Once again, apply a small amount of clean transmission hydraulic oil onto the gasket. Wipe base with clean rag and install the new filter by turning clockwise until the gasket is seated. Turn the filter an additional one half turn using your filter or strap wrench. 
  10. Refill Your Engine Transmission Oil Tanks. Using an oil funnel, add about 8.2 gallons of Yanmar TF500A hydraulic oil into the fill port. Check the sight glass as you are doing this to prevent overfilling the tank. When it’s full, wipe away any residual oil from the port. 
  11. Perform a Leak Check. To ensure there aren’t any leaks, start the tractor and visually inspect the transmission and area beneath for leaks. Start with the drain plugs. Then, turn the tractor off and check each of the filter bases for leaks, too. 
  12. Cycle Your Oil. When your inspection is complete, restart the tractor. Cycle the hydraulic controls to distribute oil throughout the system. When this is done, you can lower all controls to the down position and turn the tractor off. This will allow the oil to settle. After the oil has settled, check the oil level in the sight glass. Adjust oil levels as necessary. 
  13. Update your Records. Finally, be sure to update your records and log when the service was completed. Remember that performing and logging maintenance services like these is key to maintaining your warranty and protecting  your tractor’s operational lifespan. 

For more information, be sure to check your operator’s manual, or ask your dealer.   

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Make the most of your Yanmar tractor investment by performing regular maintenance services according to the schedule in your operator’s manual. You can also get more maintenance tips from our Customer Experience Team, or check out exclusive offers in your area. Contact us online using the button below, or give us a call at 678-551-7369.

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