Tractor hydraulic fluid comes in many types. This can make selecting the right one for your tractor a daunting task. Here’s what you need to know.
Tractor Hydraulic Fluid vs. Trans-Hydraulic Fluid
Which tractor hydraulic fluid you need comes down to answering one main question: what kind of tractor do you have? The more you know about your equipment, the better you can maintain it and make sure you’re putting the right parts, fuel, and oil in it to keep it running well for a very long time.
So, the first thing about your equipment that you need to know is whether the hydraulic and transmission fluids in your tractor are connected.
Older tractors and collector tractors have separate transmission and hydraulic systems that use fluid from different reservoirs, and need separate fluids for the different systems. So, if you’re looking for oil for the hydraulic system that raises and lowers the bucket, you most likely need a universal tractor hydraulic fluid or and ISO-specified hydraulic oil. Your owner’s manual should tell you which one is recommended for your tractor. If you don’t have your owner’s manual, you should contact the nearest dealership that sells or services tractors with the same make as yours. You will need to know the year, make, and model of your tractor to do this. They should be able to look up the manufacturer recommendations for you. Once you find the specified weight of oil you need, you may find that some hydraulic oils are labeled “ISO,” and others “AW.” These oils are the same weight, but AW oil also has anti-wear properties, hence the name. AW oils are generally superior to ordinary ISO oils for use in older tractors. Below is a reference table that will help you convert oil weight to ISO or AW rating.
SAE-to-ISO Oil Conversion Chart
15W or 20W 46
In most modern tractors, especially those built after 1980, the hydraulics and transmission draw fluid from the same reservoir. These tractors require a trans-hydraulic fluid. This simplifies things. Different tractor manufacturers have different specifications for the trans-hydraulic fluids that should be used in their equipment. You should always use a trans-hydraulic fluid that says on the label that it meets the specifications of your tractor’s maker. There are also universal trans-hydraulic fluids that meet the specifications of most tractor manufacturers.