Gear Oil. ACDelco Select Gear Oil GL5 is an extreme pressure gear oil meeting API GL-5 formulated with selected high quality base oils and special "Extreme Pressure" additives. The engine can benefit from the highest pressure-absorption capacity as well as attrition and rust prevention. Performance Standard: Meets the requirements of API Service categories GL-5 and GL-4 Includes: Good low temperature behavior. Remains in grade even when subjected to heavy loads. The lubricating film remains stable under very high loads. Foaming is minimal at high speeds. Compatible with all elastomers & other sealing materials. Outstanding protection against wear *By request/order.