A laboratory technique for the evaluation of automotive gear oils of API GL-4 level

Automotive gear oils, as typically used in rear axles, are normally evaluated in terms of their performance in full-scale bench tests. One such test is the CRC L-19/CRC L-42 test, which is included in API and other specifications. The L-19 test method is now obsolete, and the L-42 is used basically to define GL-5 level oils. An indigenous test method, IIP Method VAV-382, has been developed at the Indian Institute of Petroleum on an Amsler machine, operating under sliding conditions between two discs, and is also included in the IS:1118-92 specification for multi-purpose gear oils for GL-4 level oils. This method has been re-examined to obtain better resolution of scuffing of the disc surfaces. The modified procedure has proved effective, and the procedure and results for various commercial oils are described in this paper, which shows the method to be effective for the evaluation of GL-4 level oils.