ASTM D7038 Standard Test Method for Evaluation of Moisture Corrosion Resistance of Automotive Gear Lubricants
4. Summary of Test Method
4.1 This procedure uses a new hypoid differential assembly as the primary test unit. The differential assembly is installed on a motoring rig and charged with test lubricant and a small amount of water. The test unit is then sealed and driven until the lubricant temperature has increased to 180 °F (82.2 °C). The motoring phase is continued for 4 h and the test unit is then removed from the motoring rig and placed in a storage box for 162 h with the lubricant temperature controlled at 125 °F (51.7 °C). The test is completed at that time and the differential assembly is drained, disassembled, and inspected for rust, stain, and other deposits.
5. Significance and Use
5.1 This test simulates a type of severe field service in which corrosion-promoting moisture in the form of condensed water vapor accumulates in the axle assembly. This may happen as a result of volume expansion and contraction of the axle lubricant and the accompanied breathing in of moisture-laden air through the axle vent. The test screens lubricants for their ability to prevent the expected corrosion.
5.2 The L-33-1 test procedure is used or referred to in the following documents: ASTM Publication STP-512A, SAE J308, SAE J2360, and U.S. Military Specification MIL-PRF-2105E.
