Overview
The ZF 0501.213.026 GEAR PUMP is a critical hydraulic component engineered specifically for the WG250, WG251, and WG260 series transmissions. This OEM genuine part is responsible for generating the necessary oil flow and pressure to actuate clutch packs, lubricate internal gears, and maintain thermal stability within the transmission housing. Positioned directly on the pump drive section of the main case, the SKU 0501.213.026 ensures precise volumetric displacement for consistent shift quality. When installed alongside a robust TRANSMISSION HOUSING, this pump forms the backbone of the hydraulic circuit, delivering reliable performance under heavy industrial loads.
Symptoms of Failure
- Erratic or delayed gear engagement: A worn 0501.213.026 pump cannot maintain adequate line pressure, causing hesitation or harsh shifts during acceleration.
- Audible whining or cavitation noise: As internal clearances increase, the pump draws in air, producing a high-pitched whine from the transmission housing area.
- Visible oil seepage around the pump flange: Degraded seals allow hydraulic fluid to escape, often pooling near the HOUSING interface.
- Overheating transmission fluid: Insufficient flow from a failing gear pump leads to elevated sump temperatures, reducing overall drivetrain efficiency.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 0501.213.026 |
| Type | External Gear Pump |
| Displacement (est.) | 12.5 cc/rev |
| Maximum Pressure | 25 bar (362 psi) |
| Material | Hardened Steel Gears / Aluminum Housing |
| Weight | 2.8 kg (6.2 lbs) |
| OEM Reference | ZF 0501.213.026 |
| Mounting Torque | 45 Nm (using HEXAGON SCREW fasteners) |
Compatibility
This genuine gear pump is factory-specified for the ZF WG250, WG251, and WG260 series powershift transmissions. It is also backward-compatible with earlier WG180 and WG200 variants where the pump drive pad matches the COVER interface dimensions. Always verify the pump cavity depth and dowel pin alignment within the main housing before installation. For transmissions requiring a replacement COVER SHEET, confirm the gasket thickness matches the 0501.213.026 flange profile.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4646101028 | TRANSMISSION HOUSING | Main structural case enclosing gear sets |
| 4646301095 | HOUSING | Intermediate support for pump and valve body |
| 4646301087 | COVER | Seals the pump cavity and retains bearings |
| 0636015304 | HEXAGON SCREW | Fastens pump assembly to housing |
| 0636101828 | CAP SCREW | Secures cover plate to pump body |
| 4646301102 | COVER SHEET | Thin gasket for pump-to-housing seal |
| 4646301098 | COVER SHEET | Alternate thickness gasket for clearance adjustment |
| 0730365125 | TYPE PLATE | Identification tag for transmission model |
| 0631311009 | GROOVED STUD | Alignment dowel for pump positioning |
| 0636101193 | CAP SCREW | Bolt for securing cover sheet assembly |
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