The paper analyzes causes of the vibroacoustic activity in gears and considers ways of solving this problem. The authors address internal dynamic processes in the adaptive cylindrical gear with arched teeth that has a load-bearing advantage over spur and helical gears. The interacting parts of such gears are a pinion, two half-gears, and a set of elastic elements that make the transmission self-aligning. The research presents mathematical expressions to calculate natural frequencies of half-gears, which depend on characteristics of elastic elements, elastic characteristics of gear meshing, as well as reduced masses of parts participating in meshing. Calculating natural frequencies of half-gears with the known characteristics of the mechanical system allows us to select the properties of the elastic elements that exclude the resonance phenomena, depending on the operating frequencies of the rotating parts of the gear train.