Overview
The ZF 4644.125.473 INDUCTIVE SENSOR is a critical electronic component designed specifically for the WG200 series transmission. This OEM genuine part monitors rotational speed and position of internal shafts by generating a magnetic field that detects metallic targets without physical contact. Installed within the transmission housing, it sends real-time data to the control unit to ensure precise gear engagement and clutch modulation. The SKU 4644.125.473 is engineered to withstand high temperatures and vibration, making it essential for reliable operation in heavy-duty commercial vehicles.
Symptoms of Failure
- Erratic gear shifting or delayed engagement – A failing inductive sensor often causes the transmission to hesitate or shift harshly, especially under load, as the control unit receives inaccurate speed signals.
- Transmission slipping in higher gears – When the sensor wears out, the system may misinterpret output shaft speed, leading to unintended clutch disengagement and power loss during highway driving.
- Check transmission warning light with fault codes – Many operators report intermittent dashboard warnings related to speed sensor circuit faults (e.g., P0720 or P0722) that clear after restart but return under sustained operation.
- No start or limp mode activation – A completely failed sensor can prevent the transmission from engaging any gear, forcing the vehicle into a reduced-power limp mode until the part is replaced.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.125.473 |
| Type | Inductive Proximity Sensor |
| Operating Voltage | 10–30 V DC |
| Output Signal | Digital (NPN/PNP, normally open) |
| Housing Material | Stainless steel with PTFE seal |
| Thread Size | M12 x 1.5 |
| Overall Length | 55 mm |
| Weight | 0.045 kg |
| OEM Reference | ZF 4644.125.473 |
| Operating Temperature | -40°C to +125°C |
Compatibility
This inductive sensor is engineered for the ZF WG200 series transmissions, including the WG180, WG200, and WG210 variants. It is commonly used in buses, fire trucks, and heavy-duty construction vehicles equipped with these ZF automatic gearboxes. The sensor mounts directly into the TRANSMISSION HOUSING (4644101212) or the TRANSMISSION HOUSING (4644301221), depending on the specific build. Always verify the TYPE PLATE (0730365067) on your unit to confirm compatibility before installation. The sensor is secured using a GROOVED STUD (0631311009) to prevent loosening under vibration.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101212 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4644301221 | TRANSMISSION HOUSING | Alternate housing variant for WG200 |
| 0730365067 | TYPE PLATE | Identification plate with transmission specs |
| 0631311009 | GROOVED STUD | Fastener for sensor mounting |
| 4644303060 | COVER PLATE | Seals sensor access port |
| 4644303061 | COVER PLATE | Alternate cover plate design |
| 4644221031 | SCREEN TUBE | Oil filter screen for lubrication circuit |
| 0634306531 | O-RING | Seals sensor-to-housing interface |
| 0634306525 | O-RING | Alternate seal for sensor bore |
| 0636305026 | SCREW PLUG | Closes unused sensor ports |
