Abstract
Aim at the phenomenon of abnormal noise caused by clutch engaged under engine idle speed, this paper carries through transmission test rig and practical on vehicle test, uses frequency spectrum technology to gain the typical areas vibration and noise signals, recognizes noise resources, studies its producing, forming, propagandizing and effect. Further more it brings forward effective control measure to eliminate abnormal noise. The validate test indicates the modified transmission has decreased 3~4dBA noise during vehicle idle speed operation and improve ride comfort ability.