Overview
The ZF 4657.201.044 TUBE for WG191/WG211 is a precision-engineered hydraulic conduit that directs pressurized transmission fluid within the valve body assembly. This OEM genuine part, identified by SKU 4657.201.044, ensures proper lubrication and clutch actuation pressure in ZF WG191 and WG211 series transmissions. As a critical fluid path component, it works in concert with the 4657120005: PRESSURE REGULATOR to maintain consistent hydraulic flow. The tube is manufactured from corrosion-resistant steel to withstand continuous exposure to hot transmission oil and high operating pressures.
Symptoms of Failure
- Hydraulic fluid seepage around valve body connections – Cracks or pitting in the tube wall cause visible oil drips beneath the transmission, often mistaken for pan gasket leaks.
- Erratic gear engagement or delayed shifts – A compromised tube reduces line pressure, leading to soft clutch application and hesitation when shifting between forward and reverse.
- Transmission overheating – Restricted fluid flow through a damaged tube forces the pump to work harder, elevating sump temperatures beyond normal operating range.
- Whining noise from the transmission pump – Air ingestion through a fractured tube creates cavitation, producing a high-pitched whine that intensifies under load.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4657.201.044 |
| Material | Seamless drawn steel, zinc-plated |
| Overall Length | 185 mm |
| Outer Diameter | 12 mm |
| Wall Thickness | 1.5 mm |
| Weight | 0.09 kg |
| OEM Reference | ZF 4657.201.044 |
| Operating Pressure | 12–18 bar |
Compatibility
This tube is specifically engineered for ZF WG191 and WG211 series transmissions used in off-highway equipment, wheel loaders, and material handlers. It also fits select variants of the WG180 and WG200 series where the valve body layout matches the WG191 architecture. Always verify the part number against your transmission serial plate. The tube interfaces directly with the 0501211384: VALVE and the 0630532183: INDENTED RING that secures it in place. For complete hydraulic circuit restoration, pair this tube with the 4656306145: PISTON to ensure proper clutch piston sealing.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4657120005 | PRESSURE REGULATOR | Maintains system hydraulic pressure within specified limits |
| 0501211384 | VALVE | Directs oil flow to clutch packs and torque converter |
| 0630532183 | INDENTED RING | Locks tube into valve body bore |
| 4656306145 | PISTON | Converts hydraulic pressure into mechanical clutch engagement |
| 0732042767 | COMPRESSION SPRING | Returns piston to neutral position when pressure drops |
| 0631612064 | SET SCREW | Adjusts valve stroke limit |
| 0631610026 | SET SCREW | Secures pressure regulator adjustment |
| 4657101049 | TRANSMISSION HOUSING | Main structural casing for gear train and valve body |
| 4657301130 | HOUS.FRONT SECT | Front section of transmission housing |
| 4657301131 | HOUSING REAR PART | Rear section of transmission housing |
Frequently Asked Questions
Q: Can I reuse the old indented ring when replacing the tube?
A: No. The 0630532183: INDENTED RING deforms during installation and must be replaced with a new one to prevent tube movement and subsequent fluid leaks.
Q: Will this tube fit a ZF WG180 transmission from 1998?
A: It may fit if the valve body uses the same port spacing as WG191. Measure the center-to-center distance of the tube ports; if it matches 185 mm, compatibility is likely. Always cross-reference your transmission serial number.
Q: What torque should I apply to the set screws securing this tube?
A: Use 8 N·m for the 0631612064: SET SCREW and 12 N·m for the 0631610026: SET SCREW. Over-tightening can distort the tube bore.
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