The principal function asliding-mesh type, constant of the gearbox is mesh type and planetary type 2.The gearbox provides b). the simplest one and histori- cally oldest 3.Gearbox can be c).to vary the speed of the car 4.The sliding-mesh gearbox is d). four forward speeds and one … reverse 5.The constant-mesh gearbox e). the most widely used. is