Overview
The ZF 4644.311.237 PUMP FLANGE is a critical OEM genuine component designed for the WG 180 Series transmission. This precision-machined flange serves as the primary interface between the hydraulic pump and the transmission housing, ensuring secure mounting and proper alignment of the pump drive gear. By maintaining a leak-free seal and stable torque transfer, this part directly supports consistent hydraulic pressure for clutch engagement and gear shifts. The SKU 4644.311.237 is engineered to ZF’s exacting tolerances, making it essential for any rebuild or repair of the WG180 power take-off assembly.
Symptoms of Failure
- Hydraulic fluid seepage around the pump mounting area: A worn or cracked pump flange often leads to oil weeping at the joint between the pump and the TRANSMISSION HOUSING, resulting in gradual fluid loss and potential overheating.
- Intermittent gear slipping under load: When the flange distorts or fatigues, pump drive alignment shifts, causing irregular hydraulic pressure and delayed or slipping gear engagement during heavy operation.
- Abnormal pump noise or vibration: A loose or damaged flange allows the pump to wobble, producing a distinct whining or knocking sound that intensifies with engine RPM.
- Difficulty maintaining transmission temperature: Reduced pump efficiency from a misaligned flange can cause the transmission to run hotter than normal, triggering warning lights or thermal shutdowns.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4644.311.237 |
| Material | High-strength cast iron (GGG-40 equivalent) |
| Outer Diameter | 185 mm |
| Bolt Hole Pattern | 6 x M12 on 150 mm PCD |
| Weight | 2.3 kg |
| OEM Reference | ZF 4644.311.237 |
| Surface Finish | Phosphate coated for corrosion resistance |
Compatibility
This pump flange is primarily specified for the ZF WG 180 Series transmissions, including models WG180, WG180C, and WG180E. It also fits select variants of the WG200 and WG150 series where the pump mounting interface shares the same bolt pattern and pilot diameter. Always verify compatibility by cross-referencing the existing flange or consulting the transmission’s TYPE PLATE for exact model identification. For proper installation, ensure the mating surface on the TRANSMISSION HOUSING is clean and free of burrs, and use a new O-RING (part 0634306525) to prevent leaks. Secure the flange with the correct GROOVED STUD (part 0631311009) to achieve the specified torque.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101131 | TRANSMISSION HOUSING | Main structural casing for gear and shaft assembly |
| 4644301228 | TRANSMISSION HOUSING | Alternate housing variant for WG180 series |
| 0730365067 | TYPE PLATE | Identification plate with transmission model and serial |
| 0631311009 | GROOVED STUD | Threaded fastener for pump flange mounting |
| 4644301298 | COVER PLATE | Seals unused pump port openings |
| 0634306525 | O-RING | Elastomeric seal between flange and housing |
| 0636305026 | SCREW PLUG | Closes threaded oil passages in the flange |
| 4475280078 | ADAPTER | Converts pump flange to alternate pump sizes |
| 0501316470 | BREATHER | Vents internal transmission pressure |
| 4644301279 | SCREEN SHEET | Filter mesh for hydraulic oil return line |
