Analysis on the Noise for the Different Gearboxes of the Heavy Truck

Table 1

The pass-by noise values of assembling the three gearboxes.

Noise (dB)	4-speed	5-speed	6-speed	7-speed	8-speed
Type I	78.9	80.3	86.9	82.5	81.4
Type II	78.6	79.5	81	81.3	81.4
Type III	79.1	80.3	83	83.4	82.4