High Horsepower and High Torque Performance of EP Gear Lubricants

In recent months a series of premature gear failures in field operated vehicles produced indications of insufficient load carrying qualities in extreme pressure lubricants of the GL-4 specification conforming to the new Military L-2105A. This condition prompted dynamometer testing in an investigation of horsepower absorption and high torque absorption of these lubricants as compared with extreme pressure lubricants conforming to Military L-2105 specifications. The results of the dynamometer testing showed that lubricants conforming to the new Military L-2105A were capable of withstanding continuous high horsepower applications where relatively low torque was required, but were not able to compare favorably with the extreme pressure lubricants of the Military L-2105A specification in regard to continuous high torque applications. The gear-tooth surfaces on such tests with lubricants conforming to the new Military L-2105A were severely scored, whereas the Military L-2105A lubricants produced a satisfactory tooth condition under identical testing conditions.