Universal tractor lubricants OilChat#17

tractors working

This is not an optical illusion.

Tractors don’t come up on our radar screens all that often but modern farm equipment is a far cry from the “mechanical plow horses” of yesteryear. These new machines may still not break any speed record, but space technology is now being incorporated into agricultural equipment in the form of GPS devices, onboard computers, auto-steer system and even driverless technology!

Notwithstanding this array of state-of-the-art gizmos, lubrication still plays a critical role in the efficient and reliable operation of agricultural machinery. Tractors and other farm equipment, such as combined harvesters, have various components that need to be lubricated. These include the engine, transmission, final drives, oil immersed ( wet ) brakes hydraulic system and the power take-off ( PTO ). Just imagine the cost consequences if farmers had to stock different oils for all these applications. Furthermore, with so many lubricants in the oil store, there is also the risk of using the wrong oil for a specific component. It is therefore no wonder that agricultural equipment manufacturers and oil companies have worked together to come up with multifunctional lubricants:

Super Tractor Oil Universal (STOU/SUTO)

These oils fulfill several roles and make machine maintenance much simpler. They also reduce the number of lubricants farmers need to keep around because they can generally be used for all the applications mentioned above. When you peruse the product data sheet of a reputable STOU you will find that it meets the requirements of a host of Industry and Equipment Manufacturers’ (OEM) specifications. These may include, but are not limited to, the following:

  • Engines: API CG-4/SF
  • Gears: AP GL-4
  • Transmissions: ZF TE-ML 06A / 06B / 06C / 06G
  • Wet Brakes: Case MS 1317
  • Hydraulics: Eaton Vickers M-2950-S.

A STOU fluid can be described as a general-purpose farm lubricant with reasonable engine performance, fair load carrying capacity for gears and moderate hydraulic oil performance. However, as engines become more demanding, transmissions more sophisticated and hydraulic system pressures higher, trying to meet all the requirements with one fluid becomes more complicated. For instance, if a manufacturer recommends an API CI-4 performance level oil for the engine, two separate lubricants may have to be used since it is unrealistic to expect a single oil to meet API CI-4 and all the other service categories mentioned above. In such an instance it would be advisable to use a dedicated engine oil and a higher performance multifunctional lubricant for the other components.

Universal Tractor Transmission Oil ( UTTO )

These lubricants are also referred to as Tractor Hydraulic Fluid ( THF ) or Transmission, Differential and Hydraulic ( TDH ) fluid. They are used where the equipment manufacturer recommends a separate engine oil. UTTOshave no engine oil credentials, better hydraulic oil performance and improved wet brake fluid characteristics.

When you compare STOU and UTTO product data sheets you may well find they have some transmission, rear axle, wet brake and hydraulic oil specifications in common. However high-performance UTTOs will boast with OEM specifications that are unlikely to be met by STOUs such as:

  • Case MS 1207: Hy-Tran Plus, transmissions, hydraulics, wet brakes
  • Massey Ferguson CMS M 1141: Transmissions, hydraulics, highly loaded wet brakes
  • Volvo 97302-10: Transmission with built in wet brakes

As tractors become more sophisticated and require higher quality oils for satisfactory performance, there will most likely be an increased trend away from the all-purpose STOU fluid to a specific engine oil and UTTO combination.

TO-4 Fluid

UTTOs should not be confused with TO-4 fluids. UTTOs are mainly used in agricultural applications, although they are sometimes recommended for construction machines, such as Bell ATDs. TO-4 fluid originates from the Caterpillar TO-4 ‘Transmission Oil’ specification. TO-4 has become a standard term used within the industry for a specific type of additive/ fluid. TO-4 fluids normally meet Allison C4and other OEMrequirements as well.

Although both UTTOs and TO-4 fluids are designed for wet brake applications, they are not interchangeable since they have different frictional properties.Construction machinery, for which TO-4 fluids are intended, is normally much bigger and heavier than agricultural equipment. A higher level of friction is required to ensure that these heavy machines can stop on steep slopes, such as access roads down open cast mines.Tractor size, and therefore weight, is limited, as they need to use public roads, and therefore less friction is required to stop agricultural equipment. This results in TO-4 fluids having a higher coefficient of friction than UTTOs. Using the wrong fluid will mean that fluid/brake surface interaction will be affected and thereby reducing braking efficiency with possible catastrophic results.


Know your equipment manufacturer’s recommended lubricants, have them on hand and pay attention to tractor and equipment service intervals. If in doubt our experts are at your disposal, ready to provide you with advice and to answer any of your questions. For more information, please visit www.bcl.q8oils.co.za