How to Check Hydraulic Fluid on John Deere Tractor?

Most individuals with any mechanical inclination know about fuel and oil to make an engine run smoothly. But a lesser-known fluid is just as important and needs to be maintained and changed, or else your John Deere tractor will not perform correctly. This crucial liquid is hydraulic fluid, and it is needed for a variety of tasks that garden tractors undertake regularly.

Key Points:

  • Hydraulic fluid is an essential part of a John Deere tractor, and it needs to be regularly checked.
  • Two methods that can be used to check the fluid level are the dipstick gauge and sight glass gauge.
  • Ensure you know which fluids will work with your tractor, wipe grime from the top of the tank, place the machine in a level position for accurate readings when performing a fluid check or change.

The steps to checking your John Deere tractor’s fluid level are extremely similar to looking at oil levels and other fluid reserves. For maximum performance from the hydraulic pump, I always try to keep all fluid reservoirs at an optimum level.

Over the years, I have fine-tuned a fluid level checking system that prevents the levels of fluid from ever dropping below the proper level resulting in sluggish operations. Read on to learn the easy way to check tractor hydraulic levels in John Deere equipment. 

How To Check Hydraulic Fluid in Tractors?

 For most tractor models performing a fluid check is done in one of two ways. The method most familiar with machine operators is a dipstick gauge. On most newer models and high-end equipment, it can be even easier to stay on top of types of fluid running through your machine with the use of a sight glass gauge. Regardless of the method used, there are some things you should consider before beginning a fluid check and change. 

You must always make sure you know which fluids will work with your tractor; not all products are interchangeable. Although there are some universal hydraulic fluids, always check John Deere’s list of approved fluids in your manual or online. You also need to decide if you will be topping off the liquid or performing a full oil change.

Both of these require different oil temperatures to protect hydraulic equipment, give you an accurate reading, and allow you to perform your maintenance with minimum effort. 

Once you are ready to check the oil level, you need to set the equipment in the correct position, or the reading in the dipstick tube will be inaccurate. Park the machine on level ground and lower attachments to return bucket cylinders to the start position and push the fluid back into the reservoirs and out of the internal hydraulic systems.

This also prevents head injuries when checking fluid levels caused by raised buckets and other hazards. Once it is safe to do so, choose your method for checking your hydraulic liquid. 

Dipstick Gauge

The dipstick method is tried and true, and the measurements on a fluid dipstick are an accurate way to fill and refill your liquid reservoirs. When getting started with a hydraulic reservoir dipstick, always wipe the top of the tank, so you don’t get dirt into the reservoir or on the dipstick. Dirt in any fluid will lead to a dropoff in performance. 

The cap on John Deere tractors is usually behind the driver’s seat, not under the engine cover, and can be easily identified by the words hydraulic fluid only stenciled into the cap. To check, pull out the dipstick, wipe the fluid off with a clean cloth or paper towel, reinsert the stick, pull it out again, and take note of the levels. Based on the results, either replace the cap if levels are good or proceed with refilling if that’s what is needed. 

Sight Glass Gauge 

To quickly make sure your hydraulic fluids are at an acceptable level whenever hydraulic issues start, John Deere has equipt their machines with a sight glass gauge. This durable, transparent glass tube allows an operator to quickly see oil levels for validation purposes without the tedious dipstick process.

Being able to rule out hydraulic fluid issues quickly by sight is the main advantage of a glass gauge. 

You need to locate the hydraulic reservoir and the sight glass to proceed. Make sure to wipe off any grime or dirt that is interfering with a clean reading. Once you find the tube, you can look closely to see the scale of the fluid level, with lines denoting maximum and minimum levels. To fully lubricate hydraulic pump motors, make sure the fluid level is just below the highest line on the gauge. Never overfill or let the fluid drop below the minimum line, or equipment failure may occur. 

How Often Do Tractors Need Hydraulic Fluid?

Checking your tractor’s fluid can be done regularly to keep on top of any potential issues, but all equipment has a recommended service time frame. John Deere recommends checking the fluid after 50 hours of operation or about once a week for heavily used machines. Usually, some fluid can be added at this point. Simply topping off the fluid is all it takes to keep the machine running smoothly until a complete oil change is needed. 

Hydraulic fluid changes are also needed at bi-monthly with regular use or more often in other specific circumstances. The rated life of hydraulic fluid actively running in a machine is 1,200 hours of use or 50 days. With regular use, this should be the only time you need to worry about draining and replacing the fluids and filters.

After an extended period of heavy use, like a big project, or after the machine has been in long-term storage are also excellent opportunities to change the fluid and maintain the equipment effectively. 

How Do Hydraulics Work

The basic principles of hydraulics are simple liquid is used to transfer force inside of equipment making heavy-duty work possible with minimal effort. In modern equipment, electronics control the specifics of the hydraulic systems, such as where the fluid goes and how much pressure is generated, but the fluid generates the actual mechanical force in the hoses being forced into smaller and smaller cylinders.

The hydraulic fluid lubricates all moving parts and becomes pressurized as it gets squeezed through the chambers serving several purposes, making it much more effective than other pressurized liquids. As the hydraulic fluid generates force, some oil flow through valves and hoses to lubricate friction zones and help all moving parts last longer.

The typical build-up of pressure results in 2000 psi per square inch, more than enough to perform the amazing tasks tractors accomplish. 

ValvesAllow Containment of Fluid in Hoses for Pressure adjustments and Maintenance
PumpMoves Fluid through the Hose
ReservoirHolds the Fluid Until Needed For Lifting
FluidThe liquid that Cannot be Compressed and Will Not Overheat
CylinderPushes Fluid Through Itself to Create Pressure
HoseThe conduit through which Hydraulic Fluid Flows
FilterKeeps Fluid Cleaner for Longer Continued Use
MotorPower Source

Mechanical Force

Cylinders, pumps, and motors generate the pressure that allows the hydraulic fluid to convert to physical energy. This mechanical force translates to buckets and other attachments being moved precisely with almost no exertion on the driver’s strength. This makes a tractor effective at completing heavy-duty tasks with tons of force generated per square inch and precision with the hair-trigger movements superior hydraulic systems provide. 


As large parts of a John Deere tractor move and operate, both tremendous heat and volatile friction are produced. If a machine is not lubricated, the results can be catastrophic. Due to hydraulic fluid dynamics, as some fluid generates pressure for movement, other volumes of liquid are diverted through valves and hoses to lubricate and cool moving non-engine parts.

You can drain hydraulic fluid from multiple valves to fix specific areas that are causing trouble without dumping everything out of the reservoir. This saves fluid and helps you get back to the task at hand faster. 

How To Refill and Change Hydraulic Fluid

Super S Anti-Wear AW32 Hydraulic Oil for Log & Wood Splitters, Gear & Compressor Oil- Rust & Corrosion Protection- 1 Gallon

Optimal performance comes from well-maintained equipment. While it might make sense to take a car to the mechanic for things like an oil change, there is no need to call a repair service company just to deal with the hydraulic fluid in your system. Some standard practices are to get the oil temperature to 45 degrees C if you will be doing a full change.

Since the hydraulic fluid is manufactured clear, different colored fluid additives make it easier to see the level in glass sight gauges and on dipstick, but ultimately the exact steps depend on the type of hydraulic fluid you will be using. 

Mineral-based Fluids

A common additive that is cheap and effective and does well for long-term storage. The mineral oil in the fluids has additives that prevent rust and oxidation within the tractor, making your fluid last longer and protecting vital machine components. While not as long-lasting as synthetic fluids, mineral-based liquids are a good option and outperform water-based fluids. 

Water-based Fluids

These are the cheapest and very common but lack the durability of other, more synthesized formulas. Water-based fluids are fire-resistant and can prevent heat transfer through metal parts that may lead to overheating. While it is able to be pressurized and performs lubrication throughout the systems, changes and filter replacement will be needed more frequently. 

Synthetic Hydraulic Fluids

If you have the budget, synthetic hydraulic fluids are the best choice as they offer properties of both mineral and water-based fluids. Some configurations of tractors may use a type of rubber that reacts with the fluid, and in that case, this liquid may not be suitable for your tractor’s gaskets. Always check the user’s manual before adding fluid if you are not 100% sure it is right for your machine. 


Most hydraulic fluid maintenance will revolve around refilling the reservoir. This is easy to do if you have the right tools and follow the steps below. If you haven’t already, clean all the dirt and grime off of the cap and the area around your hydraulic tank opening. Once that’s done, insert a clean funnel into the tank.

Pour slowly to avoid spillage, and keep a steady eye on the max fill line. Pouring slowly also prevents air bubbles from forming in the liquid, which can affect performance later on. 

To prevent overfilling or underfilling, make sure the tractor is parked on level ground, and the bucket cylinders are in the start position. When refilling, you do not need to heat up the fluid; if the engine is cool, you will get a better reading, and all the fluid will be settled. Add the liquid when the engine has cooled down completely. 


Changing the fluid in the hydraulic reservoir is less frequent and requires different steps. In the case of a full drain, you will want to run the engine and get the fluid up to around 45 degrees C. This will help everything to drain out quickly and allows the fluid to pick up impurities in the system that can be emptied with the flowing fluid.

When ready, open the plug under the tank and let the fluid drain into a bucket or other approved container. 

While the reservoir is draining, you can clean any reusable screens and replace dirty filters. When all of the fluid has drained, you need to replace the plug. Failure to do this will result in a mess when you go to top off your liquid. Choose the best fluid for your machine and then add it using the same steps from the refill process.

Once full, allow the engine to run for 1 minute to give the fluid a chance to flow through the system and to see if everything is working properly. Engage the hydraulics and power steering to test the liquid saturation. Checking your John Deere hydraulic fluid is easy and necessary to keep your equipment running strong for a long time.