1970 CST/10 Speedometer / Transducer Question

[rmawyer]

Working on speedometer that never worked (needle not moving). Got new transducer for eventual restore of cruise control. Bypassed transducer and hooked new speedometer cable directly to transmission. Good news speedometer working but bad news it is showing twice the speed (40 MPH displays around 80 MPH, etc.). Does the transducer have anything to do with the double speed? Do I need to hook speedometer to transducer to transmission to reduce the speed or am I in a transmission gear replacement state? As always thanks for assistance. Bob