Alisyn ProGear 21 Type 1 gearcase oil carries a viscosity rating of less than 0W while  providing needed gear protection and increasing potential performance.

Oil. Regardless of horsepower rating, lubricating oil is the one thing all internal combustion engines depend on as a core element of their function. The quality of oil used is a key variable in how well an engine performs under demanding conditions and for extended periods of operation. While there are other obvious factors that determine engine life, using a quality oil is of critical importance to the taxing demands of high RPM, high performance outboard engines.

Most people are familiar with the basic types and brands of two-stroke oil consumed by these engines; however one area overlooked is the oil used in the gearcase. The gearcase of an outboard or stern drive is analogous to the transmission in an automobile, meaning that it channels engine power through a reduction gear system to deliver usable power.

Typically, the lubricant used in the gearcase is a high-viscosity (90W) formulation derived from a petroleum or synthetic base.

The gearcase lubricant has three critical duties:

Evaluating Pro Gear 21 Type 1

Traditional gearcase lubricants have a viscosity rating of 90W, which provides extreme load and heat protection.

Aerospace Lubricants is well known among hardcore automotive and boat racers for their line of Alisyn fully synthetic oils. What makes Alisyn stand out among other leading synthetic oils on the market is the unique and highly guarded additive package that allows Alisyn gear oil to provide more protection from a lighter viscosity formula, namely, ProGear 21 Type 1.

Alisyn’s custom gear formulas and exclusive additive package were developed through years of extensive race testing and refinement in such applications as SCCA Endurance Cars, Pro Stock, and Pro Modified drag cars, and more importantly, high performance marine gearcases.  Additionally, ProGear 21 Type 1 is designed to handle necessary loads while reducing internal gearcase temperatures.

In addition to its primary function of lubricating gears and displacing loading pressures and heat, the Alisyn ProGear 21 oil contains various demulsibility agents, which help retain the oil’s effectiveness, even when water is introduced into the lower unit. This was of particular concern to us, since we felt the lighter oil weight could possibly allow water intrusion in the presence of worn or weakened seals.