Automatic Transmission Speed Sensors

Fig 1: Automatic Transmission Speed Sensors

Courtesy of GENERAL MOTORS COMPANY

The 10 speed transmission has four speed sensors mounted internally to the transmission case above the valve body:

• Input Speed Sensor (4)
• Intermediate Speed Sensor 1 (3)
• Intermediate Speed Sensor 2 (2)
• Output Speed Sensor (1)

All four speed sensors operate the same way, but measure the rotational speed of four different components. These sensors are two wire hall-effect type sensors. The TCM supplies a 9 V reference circuit and a signal circuit to each sensor. As each sensor reluctor wheel rotational speed increases, the frequency output signal from each sensor increases. The scan tool displays this as a RPM value. The TCM uses the RPM value from each sensor to determine transmission line pressure, shift patterns, correct gear ratio and the torque converter clutch slip speed.

Input Speed Sensor 

Fig 2: Input Speed Sensor

Courtesy of GENERAL MOTORS COMPANY

The input speed sensor is also known as the automatic transmission turbine speed sensor. A 40 tooth reluctor ring is splined to the transmission input shaft.

Intermediate Speed Sensor 1 

Fig 3: Intermediate Speed Sensor 1

Courtesy of GENERAL MOTORS COMPANY

The intermediate speed sensor 1 is also known as the automatic transmission intermediate speed sensor A. A 50 tooth reluctor ring is part of the transmission reaction carrier assembly.

Intermediate Speed Sensor 2 

Fig 4: Intermediate Speed Sensor 2

Courtesy of GENERAL MOTORS COMPANY

The intermediate speed sensor 2 is also known as the automatic transmission intermediate speed sensor B. A 50 tooth reluctor ring is part of the transmission output carrier shell.

Output Speed Sensor 

Fig 5: Output Speed Sensor

Courtesy of GENERAL MOTORS COMPANY

A 68 tooth reluctor ring is part of the transmission output carrier assembly, splined to the output shaft.