F 350 4WD Super Duty V8-6.4L DSL Turbo (2008)
Transmission Speed Sensor: Description and Operation
Output Shaft Speed (OSS) Sensor
The transmission Output Shaft Speed (OSS) sensor is located on the extension housing. The OSS is a Hall-effect type sensor. The OSS reads the gear
teeth on the park gear, which are different than the teeth used for park function. The OSS input to the PCM is used for shift scheduling, TCC operation
and vehicle speed. The OSS has bi-directional capability and has a digital output.
TSS sensor and Intermediate Shaft Speed Sensor
The TSS and intermediate shaft speed sensors are both hall-effect sensors requiring ignition voltage and a ground. The other 2 terminals at the sensor are
for TSS/intermediate shaft speed sensor signal output. The TSS sensor detects teeth on the coast clutch input hub and the intermediate shaft speed sensor
detects teeth on the adjacent Overdrive (O/D) ring gear. Both read 30 teeth per revolution. The TSS and intermediate shaft speed sensors are mounted
externally on the transmission case toward the top on the driver's side. The TSS and intermediate shaft speed sensors input to the PCM is digital and is
used to determine line pressure, shift scheduling, timing and TCC operation.
