The mechanical ratio gearbox was connected to the dash mounted rear axle range knob. On my truck, the range selector is mounted on the gearshift lever and a cable runs down to the vacuum switch on the transmission. The speedo ratio gearbox is vacuum operated from that vacuum switch.
1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy
| 
