Published 17th July, 2010
The API GL-4 specification for gear oils is set to become obsolete on 31 July this year.
Accordng to Lube Report's Stephen Swedberg, the specification will become obsolete from the end of the month subject to approval from the API's membership.
GL-4 has been applied to axle gears under various load conditions However, test equipment used to verify performance of the lubes is no longer available, making it impossible to run most of the tests, according to ExxonMobil's Kevin Buzdygon, who led the debate on the spec's future.
GL-4 is generaly used for trucks and some older cars. GL-5 has taken over as the preferred specification for modern auto gear oils. API's Kevin Ferrick backed the move to make the specification obsolete, stating that the public impact of this action would be minimal.