Abstract: A procedure for qualifying a proposed synthetic lubricant includes: (1) compatibility testing the proposed lubricant with previously approved synthetic lubricants; (2) stability testing the lubricant for thermal oxidation by testing the lubricant in a heated gear box; (3) corrosion testing the proposed lubricant by a copper strip tarnish test; (4) field testing the proposed lubricant to evaluate the ability of the lubricant to withstand extended drain intervals while still performing its function; and analyzing all of the results of those tests. In another embodiment, the lubricant furthermore undergoes a seal life test to evaluate the appearance of various covers and seals for degradation due to long term exposure to the lubricant.