Overview
The ZF 4651.125.400 INDUCTIVE SENSOR is a precision electronic component engineered specifically for the WG 100 Series transmission. This OEM genuine part monitors rotational speed and position within the gearbox, sending critical data to the transmission control unit (TCU) to ensure precise shift timing and clutch engagement. Mounted directly into the TRANSMISSION HOUSING, the sensor detects ferrous targets on rotating shafts without physical contact, eliminating wear from friction. The SKU 4651.125.400 is a direct replacement for the original factory-installed unit, guaranteeing identical electrical characteristics and mechanical fitment for WG100 applications.
Symptoms of Failure
- Erratic or delayed gear engagement: When the inductive sensor fails, the TCU receives inconsistent speed signals, causing harsh shifts or hesitation when moving from neutral to drive.
- Transmission stuck in limp mode: A faulty 4651.125.400 often triggers a diagnostic trouble code (DTC) for “input speed sensor circuit,” forcing the transmission into a reduced-power safety mode.
- Intermittent loss of torque converter lockup: Worn sensors produce noisy signals, preventing the torque converter clutch from engaging properly, leading to increased fuel consumption and transmission fluid overheating.
- No start condition with no communication: In severe cases, a completely failed sensor can prevent the TCU from recognizing engine cranking, leaving the vehicle unable to move.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4651.125.400 |
| Sensor Type | Inductive (passive, 2-wire) |
| Output Signal | AC sine wave (variable frequency) |
| Housing Material | Nickel-plated brass |
| Thread Size | M12 x 1.5 |
| Overall Length | 45 mm |
| Weight | 0.035 kg |
| OEM Reference | ZF 4651.125.400 |
| Operating Temperature | -40°C to +125°C |
| Protection Rating | IP67 |
Compatibility
This inductive sensor is primarily designed for the ZF WG100 series, but it also fits the WG180, WG200, and WG250 transmissions due to identical mounting interfaces and electrical specifications. It is commonly used in off-highway vehicles, construction equipment, and agricultural machinery where ZF powershift transmissions are deployed. Always verify the sensor port location within the HOUSING assembly before installation. The sensor seals against fluid ingress using a dedicated O-RING (part 0634303928), which should be replaced simultaneously to prevent leaks. For applications requiring a different housing configuration, the HOUSING variant 4651301031 may be used as an alternative mounting base.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4651101009 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4651301025 | HOUSING | Secondary housing for sensor mounting |
| 0634303928 | O-RING | Seal between sensor and housing |
| 4651301031 | HOUSING | Alternate sensor mounting housing |
| 4651203002 | SCREEN SHEET | Filter screen for hydraulic circuit |
| 4651303005 | SCREEN SHEET | Fine mesh filter for oil return |
| 0636101032 | CAP SCREW | Fastener for housing assembly |
| 0630361028 | SEALING CAP | Protective cap for unused ports |
| 4475280060 | SCREW PLUG | Threaded plug for oil passages |
| 0634303312 | O-RING | Seal for screw plug |
