How to Change Hydraulic Oil in Gravely Zero Turn Mower

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Gravely zero-turn mowers are one of the most vintage lawnmowers with almost 100 years of legacy. These mowers are generally top-class performers on the lawn with a higher efficiency rate. To keep the top-class performance ongoing, proper maintenance is a must. Changing the hydraulic oil is one of the most crucial parts of these maintenance processes.

When you know how to change hydraulic oil in Gravely zero turn mower, maintaining the mowing machine becomes much more manageable. The filter may also need replacing, and you need to stay focused on that. The compatible oil and oil filter will ensure a smooth hydro transmission running in the mower.

Why You Should Change Hydraulic Oil in Gravely Zero Turn Mower

Gravely zero-turn mowers are a bit expensive, and having problems with them will suffer you a lot. You won’t ever want to face hydraulic-related problems during the cutting session. The primary usage of hydraulic fuel is for keeping the mower operating system and steering smooth.

Lack of fuel or faulty fuel can mess up your trimming session on the lawn. Regular changes of the hydraulic oil keep such problems away and help to gain top-class performance. Now, let’s get a detailed view on the reasons why you should regularly change the hydraulic oil in the Gravely zero turn mower:

  • To gain a smooth performance from mower operating and steering
  • Lack of hydraulic oil can suddenly shut off the mower engine
  • If you do not change the hydraulic oil, it may jam the pistons and transaxle
  • For a smooth running of the whole hydraulic system, you need to change hydro gear oil regularly
  • To keep the mower performance high for several years

The Necessary Steps to Follow on How to Change Hydraulic Oil in Gravely Zero Turn Mower

Following the right path of changing hydraulic oil will get your job done quickly. There are some steps to follow for completing the whole process. Those necessary steps for a hydro gear oil change are:

Step-1: Collecting the necessary tools and materials

When you change the hydraulic oil, some tools and materials are must to have. The essential tools you need to collect are:

Step-2: Prepare Yourself and Place the Mower

After collecting all the equipment, you need to prepare the mower for the oil changing procedure. Put on the gloves in both of your hands, and it will keep your hands safe while dealing with heavy machines. You should also put on the glasses to keep your eyes safe. 

Select a flat surface from your garden or garage and make sure that the place doesn’t contain any ups and downs. Choose an area that has proper sunlight, and everything is visible. 

Then put that mat on that flat surface, and you must pick a clean and fresh mat. Take the mower there, and place it on that mat over the flat surface.

Step-3: Disconnect the Spark Plug

After placing the mower, the next task is to disconnect the spark plug from the mower engine. As you will disconnect, it will prevent the mower from starting suddenly. Thus, you will remain safe while changing the hydraulic oil.

Step-4: Lift the Mower Body and Turn it Upside Down

You need to lift the mower body from the backside, and the jack stands are necessary for the task. Place two jack stands on either side of the rear wheels and make sure the stands are placed correctly. Then lift up the mower body by using those two jack stands. 

You can either detach the rear wheels or even keep them while lifting the lawnmower. After lifting, turn the mower body upside down to make the oil-changing task hassle-free.

Step-5: Detach the Oil Filter Cap and Loosen Oil Filter

By turning the mower body upside down, you can access the oil filter cap and oil filter. At first, take off the oil filter cap with your hands, but if it is stubborn to come out, use pliers instead. After detaching the oil filter guard, it turns to take off the oil filter from its place.

Take a wrench, and loosen the oil filter slowly and carefully. Stay focused about not detaching the oil filter, as this task will drain out the oil instantly.

Step-6: Drain out the Old Hydraulic Oil

Take the pan you kept aside at the beginning and place it right under the oil filter. After doing so, twist the oil filter and take it off from there. Then the oil will come out and fall into the pan. Wait until all the old hydraulic oil is drained out, and make sure not a single drop is left. 

Step-7: Install a New Oil Filter

At first, apply some new oil to the oil filter gasket to make the whole process smooth and hassle-free. Then mount it on the oil filter transaxle point and double-check if the oil filter is in the perfect place or not. After mounting, twist the filter carefully with a wrench or pliers to make it properly connected. 

Step-8: Pour the New Hydraulic Oil

When the new oil filter will be installed correctly, remove the oil tank’s cap and place a funnel for pouring new oil. Take the oil jar, and start pouring the new hydraulic oil into the lawnmower’s oil tank. Remain careful about not letting a single drop of oil fall outside the tank. 

When oil pouring is completed, take the funnel off from the oil tank, and install the oil filter cap. Take the paper towel you kept aside, and wipe the outer part of the oil tank body. 

Step-9: Checking

After pouring new hydraulic oil, put all the parts back together one after another. Attach the rear wheels if you had taken them off at the start of the proceedings. Connect the spark plug into the mower engine, start the mower, and start trimming grass for final checking.

Following these steps of how to change hydraulic fluid in a zero-turn mower will lessen your hassle regarding the task.


What is the best hydraulic oil for the Gravely zero turn mower?

Hydraulic oil is essential for a Gravely zero-turn mower. This fuel keeps the operating system and steering smooth to ensure hassle-free trimming sessions. But you need to make sure you are pouring the perfect and top-quality hydraulic oil into your mower. For a Gravely zero turn mower, you should use either 20W-50 motor oil or 15W-50 synthetic motor oil.

What is the necessity of changing the hydro gear fuel frequently in a Gravely zero-turn mower?

You shouldn’t change the hydraulic oil frequently without any reason. But, when somehow the hydraulic oil becomes faulty, you should change it as soon as possible. Poor quality hydraulic fluid can damage the engine, steering, and pistons. 

So, whenever the hydraulic oil in a Gravely zero turn mower is not up to the mark, you should change it without any delay.


When you keep using poor quality or faulty hydraulic oil, it may damage the mower engine. Alongside that, the operating system, steering, and pistons can also face damages. So, changing the hydraulic oil regularly is highly important for your Gravely zero-turn mower.

Completing this process will require your knowledge on how to change hydraulic oil in Gravely zero turn mower. When you know the process, you can change the fuel whenever you feel the necessity. Thus, your Gravely zero-turn lawnmower will serve for several years.

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