Overview
The ZF 4166.336.424 CIRCUIT COVER is a precision-engineered OEM genuine component designed for the WG200 and WG201 transmission series. This part serves as a critical sealing and protective barrier within the hydraulic control circuit, ensuring proper fluid routing and pressure regulation inside the transmission housing. Positioned on the valve body assembly, the circuit cover prevents contamination ingress and maintains system integrity. The SKU 4166.336.424 is manufactured to ZF’s exacting tolerances, guaranteeing a perfect fit and long service life. When paired with the TRANSMISSION HOUSING (4644101223) or the TRANSMISSION HOUSING (4644301225), this circuit cover ensures seamless integration into the transmission’s hydraulic network.
Symptoms of Failure
When the ZF 4166.336.424 circuit cover wears or becomes damaged, operators may notice several distinct failure indicators. Hydraulic fluid seepage around the valve body area is a common early sign, often appearing as wet spots on the transmission exterior. Erratic gear engagement or delayed shifting can occur due to pressure loss in the control circuit, leading to rough transitions between gears. Contaminated transmission fluid may result from the cover failing to seal out debris, causing accelerated wear on internal components. Additionally, intermittent loss of drive under load can manifest when the circuit cover no longer maintains consistent hydraulic pressure, particularly in heavy-duty applications.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number | 4166.336.424 |
| Material | Die-cast aluminum with corrosion-resistant coating |
| Dimensions (L x W x H) | 185 mm x 95 mm x 12 mm |
| Weight | 0.42 kg |
| OEM Reference | ZF 4166.336.424 |
| Sealing Surface | Precision-machined flat surface with O-ring groove |
| Operating Temperature Range | -40°C to +120°C |
Compatibility
This circuit cover is specifically engineered for the ZF WG200 and WG201 transmission series, commonly found in medium-duty commercial vehicles, construction equipment, and agricultural machinery. It is also compatible with the WG180 series when used in conjunction with the appropriate COVER PLATE (4644301298). The part fits transmissions with hydraulic control systems requiring a sealed circuit cover for the main valve body. Always verify your transmission model’s serial number against ZF’s compatibility charts before installation. For proper assembly, ensure the TYPE PLATE (0730365125) is correctly positioned to avoid misidentification during service.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101223 | TRANSMISSION HOUSING | Main structural casing for gear and shaft assembly |
| 4644301225 | TRANSMISSION HOUSING | Alternate housing variant for WG200 series |
| 0730365125 | TYPE PLATE | Identification plate with transmission specs |
| 4644301298 | COVER PLATE | Protective plate for auxiliary ports |
| 0634306525 | O-RING | Sealing ring for hydraulic connections |
| 0636305026 | SCREW PLUG | Threaded plug for fluid drain or test points |
| 4644301279 | SCREEN SHEET | Filter mesh for hydraulic fluid debris |
| 4644301088 | SEALING CAP | Cap for unused hydraulic ports |
| 4644106300 | SHIFT SYSTEM | Complete shift mechanism assembly |
| 4644306500 | COVER PLATE | Secondary cover for valve body access |
