Overview
The ZF 4651.164.400 INCHING VALVE is a precision hydraulic control component engineered for the WG 201 Series transmission family. This OEM genuine part modulates clutch pressure during low-speed maneuvering, enabling smooth “inching” or creep control without stalling the power take-off (PTO). Positioned within the valve body assembly, the SKU 4651.164.400 directly interfaces with the TRANSMISSION HOUSING (4644101160) to regulate oil flow. When paired with the TRANSMISSION HOUSING (4644301323), it ensures precise hydraulic response for heavy-duty industrial applications.
Symptoms of Failure
- Erratic inching or jerky low-speed operation: A worn inching valve causes inconsistent clutch engagement, making precise vehicle positioning difficult.
- Oil seepage around the valve bore: Degraded seals allow transmission fluid to leak past the THREADED BUSH (4644301189), leading to pressure loss and puddling under the housing.
- Delayed or harsh gear engagement: When the valve fails to modulate pressure, shifts become abrupt, especially when transitioning from neutral to drive.
- Transmission overheating during creep: A stuck valve forces continuous hydraulic slip, generating excess heat and accelerating fluid breakdown.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number (OEM) | 4651.164.400 |
| Material | Hardened steel with nitrile seals |
| Weight | 0.45 kg (1.0 lb) |
| Operating Pressure | 8–18 bar (116–261 psi) |
| Thread Size | M14 x 1.5 (inlet port) |
| OEM Reference | ZF 4651.164.400 |
| Compatible O-Ring | 0634306198: O-RING |
| Mounting Hardware | 0636100621: HEXAGON SCREW (x2) |
Compatibility
This inching valve is designed for the ZF WG 201 Series and its derivatives, including the WG180, WG200, and WG210 models. It is also compatible with select WG 202 variants used in mobile cranes and forklifts. For proper sealing, always replace the SCREW PLUG (4475280043) and O-RING (0634306198) during installation. The valve body mounts directly to the COVER PLATE (4644301161) and requires a BREATHER (0501218540) for pressure equalization.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101160 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4644301323 | TRANSMISSION HOUSING | Secondary housing for valve body |
| 4644301189 | THREADED BUSH | Seals valve bore against leakage |
| 4475280043 | SCREW PLUG | Closes hydraulic test ports |
| 0634306198 | O-RING | Provides static seal between components |
| 0730365067 | TYPE PLATE | Identification label for transmission |
| 4644301161 | COVER PLATE | Protects valve assembly from debris |
| 0636100621 | HEXAGON SCREW | Fastens valve to housing |
| 0631610020 | SET SCREW | Locks adjustment position |
| 0501218540 | BREATHER | Vents internal pressure buildup |
