To me, windage is a drag caused when an object moves through the air.

In a gearbox, lubrication losses are the additional drag caused by the gears churning the lubricating oil. ■

There are three types of losses in a typical reducer:

1. Mechanical slip between gears as they come into contact and then glide (slip or slide) between engagement and disengagement of each tooth.

2. Lube churing (dip or splash vs. pressure applied)

3. Bearing radial and thrust losses

These numbers are dependent on load and temperature. The churing is typically about 65% and other mechanical load dependent losses are about 35%.

Also, the reducer must have sufficient preload on the bearings to maintain rolling and not go into sliding. ■