Gear lubricants, particularly those of high viscosity, will act as cushions and thus reduce noise, shock, and vibrations of meshing gears. However, it must be kept in mind that even the most viscous products are not correctives for poor mechanical conditions.
Mention might be made that Cardillo,^14 in an analysis of “Initial Axle Noise” in automobiles, concluded that it is a resonance problem and apparently lubricants or lubrication plays no part in abating this noise .A different noise effect has occurred in automatic transmission and limited slip differential mechanisms of vehicles and in both cases has been corrected by the use of oiliness additives. The degree of oiliness must be carefully controlled since, if deficient, the clutch operation will be rough and cause chattering or squawking but, if excessive, the clutch may slip. Mention will be made of some of the suggested additives for this purpose in a latter section
