TASC Force Tips
- Author: Mike Steen, Certified Transmission
Their turbine-speed sensors look similar but won’t interchange
At first glance you might think the AX4S and AX4N turbine-speed sensors are the same. However, a closer look will show you that the AX4S sensor is a little longer – which means you easily could install the wrong sensor in a unit by mistake.
You also can look at the driven sprockets from an AX4S and an AX4N and not notice the subtle difference in the reluctor depth. The driven sprockets themselves are the same, and the reluctors have the same tooth count. However, the reluctor is pressed into the driven sprocket at a different depth, so you also could install the wrong reluctor in a unit by mistake.
If you’ve used incorrect combinations of parts, two different scenarios are possible.
- AX4S turbine-speed sensor with AX4N sprocket: The reluctor will make contact with the sensor and damage it.
- AX4N turbine-speed sensor with AX4S sprocket: The air gap between the sensor and the reluctor will be too great and could cause ratio codes and/or a turbine-speed-sensor code.
If you’re not sure whether you have an AX4S or AX4N driven sprocket, measure the air gap before you assemble the unit. The correct air gap between the turbine-speed sensor and the reluctor is about 0.120 inch.
If you think you might have the wrong combination of parts and the unit is already assembled, check by measuring the depth of the turbine-speed-sensor hole to the reluctor. If your measurement is 0.687-0.709 inch, you need the AX4N sensor, F5DZ-7M101-A. If your measurement is 0.759-0.772 inch, you need the AX4S sensor, F1DZ-7M101-A.
Special thanks to Gary Carlson of Certified Transmission for his help in gathering information for this article.
The TASC Force (Technical Automotive Specialties Committee) is a group of recognized industry technical specialists, transmission rebuilders and Sonnax Industries Inc. technicians.