PLUG AS-RELIEF 3278525 - Caterpillar

Service Magazine; August 28, 1989; Page 1; "Recommendations For Lubrication Oils In Powershift Transmissions".Caterpillar has released a new oil specification for the transmission and drive train defined as Caterpillar TO-4. This oil is formulated for transmissions and drive trains only, and should not be used as an engine crankcase oil. The new oil specification will replace the former TO-2 by the middle of 1991. The TO-2 has been the transmission oil specification since the middle 1970's. Future Caterpillar lubricant recommendations will specify the TO-4 oil for all Caterpillar transmissions and final drives.
The purpose of the new oil requirement is to provide the oil properties necessary for the transmission and final drive designs in use today. The new specification assures top performance and long life for all Caterpillar equipment. The TO-4 specification is the result of a comprehensive test evaluation of frictional requirements, wear tests; and viscosity, chemical, and physical properties. The TO-4 specification provides all of the necessary test requirements for a fully formulated transmission and drive train oil. The TO-4 oil also includes an evaluation of the shear stability of the test oil. When and if shear stable VI improvers for petroleum base oils are available, they can be evaluated by this test.
The current Caterpillar Transmission and Drive Train Oil (TDTO) meets all of the TO-4 requirements. This oil has been tested in proprietary full scale transmissions, final drives, and brake systems, in addition to the T)-4 requirements. Caterpillar TDTO is presently marketed in single viscosity grades only (SAE 10W, 30 and 50). However, the Caterpillar TDTO container part numbers have not changed with the introduction of the new TO-4 oil. Commercial oil products which meet the new TO-4 specification should be available on the market by the middle of 1991.
As previously announced in the Reference Article, Caterpillar does NOT recommend the use of multiviscosity oils containing engine oil type viscosity index conditioners (improvers) in Caterpillar transmissions and final drives.