SYMPOSIA PAPER Published: 01 January 1972

Laboratory Performance Tests for Automotive Gear Lubricants intended for API GL-4, GL-5, and GL-6 Services


The American Petroleum Institute has developed six lubricant Service Designations for Automotive Manual Transmissions and Axles. Each of these Designations states in qualitative terms the kind of service in which a gear lubricant is expected to perform satisfactorily. Both the type of gears and the operating conditions for the lubricant are included in each Service Designation. Supplementing of the qualitative API Designations with performance definitions is needed, particularly for Service Designations GL-4, GL-5, and GL-6. These performance definitions include a series of tests and associated minimum performance requirements. The tests and requirements for GL-4, GL-5, and GL-6 are presented in this publication. Appendix XIV presents the precision data related to these tests. Neither the lubricant classifications, nor the test techniques listed are ASTM Standards.

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Developed by Committee: D02
Pages: 1–11
DOI: 10.1520/STP45903S
ISBN-EB: 978-0-8031-6729-2
ISBN-13: 978-0-8031-6658-5