With motor oils, there are different performance levels in the market. For example, you can have a 0W-20 Full Synthetic motor oil which meets API SP and ILSAC GF-6A or you can have a 0W-20 Full Synthetic motor oil which meets API SP, ILSAC GF-6A and dexos1®Gen3. The list of specifications and their associated performance levels gives definite performance qualities of the lubricant.

The same is true in gear oils. Before you think all gear oils are the same, it is important to recognize the specifications claimed on the label and make sure it aligns with your needs. For most vehicles, there are 4 key industry specifications to look for when comparing products:

API GL-5: There have been a series of GL-X ratings over the years, and GL-5 is the most recent. Think of this as your core specification that virtually all light and medium duty gear applications call for.

Limited Slip (LS): Additive in the lubricant that gives the proper frictional characteristics for automotive applications where a Limited Slip differential is in use.

MT-1: Typically called for in non-synchronized manual transmissions used in buses and heavy-duty trucks. Provides additional protection of component wear and prevents oil seal deterioration which isn’t provided by gear oils only claiming GL-5.

SAE J2360: This is a further enhancement beyond MT-1.  It is designed to prevent sludge and deposits from forming on shafts, gears and oil seals. To pass this test, the oil cannot cause the seals to harden and deteriorate.

Of course there are other specifications set forth by some (but not all) OEMs. MAG 1 gear oils competes with top line products in the market by meeting these stringent specifications. So before you think gear oils are all the same, better check that label again!