Overview
The ZF 0501.331.027 PUMP is a critical hydraulic component engineered specifically for the WG100, WG130, and WG131 powershift transmission series. This OEM genuine part serves as the primary fluid displacement unit, 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 transmission’s pump drive adaptor, the 0501.331.027 draws oil from the sump and delivers it through the valve body to ensure consistent shift quality. When rebuilding a transmission, it is common practice to inspect this pump alongside the 2095109020: DIFFERENTIAL and the 0750117075: TAPER ROLLER BEARING, as wear in any of these components can compromise overall drivetrain reliability.
Symptoms of Failure
- Intermittent gear slippage under load: A worn 0501.331.027 pump cannot maintain adequate hydraulic pressure, causing clutches to slip during acceleration or when climbing grades.
- Low or erratic transmission oil pressure: Gauges or diagnostic tools will show pressure fluctuations below factory specifications, often accompanied by a whining noise from the pump cavity.
- Overheating and discolored fluid: Insufficient oil flow leads to excessive heat buildup, resulting in dark, burnt-smelling transmission fluid and potential damage to the 2095209037: DIFFERENTIAL.
- Delayed or harsh shifting: The transmission may hesitate before engaging gears or exhibit jarring shifts due to inconsistent hydraulic feed from the failing pump.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number (SKU) | 0501.331.027 |
| OEM Reference | ZF 0501.331.027 |
| Pump Type | Gerotor / Positive Displacement |
| Housing Material | High-Grade Aluminum Alloy |
| Weight (approx.) | 2.4 kg (5.3 lbs) |
| Overall Length | 145 mm |
| Mounting Flange Diameter | 85 mm |
| Rotation Direction | Clockwise (viewed from drive end) |
| Seal Type | Integrated O-Ring & Lip Seal |
Compatibility
This genuine ZF pump is designed for direct fitment in the following transmission models: WG100, WG130, and WG131. It is also compatible with certain variants of the WG180 and WG200 series when used with the correct adaptor plate. For complete driveline restoration, always verify the condition of the 2095309059: DIFF.HOUSING and associated bearings to prevent premature pump failure.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 2095109020 | DIFFERENTIAL | Distributes torque to axle shafts |
| 0750117075 | TAPER ROLLER BEARING | Supports rotating shafts under axial load |
| 2095209037 | DIFFERENTIAL | Secondary torque distribution unit |
| 2095309059 | DIFF.HOUSING | Encloses differential gear set |
| 0631329086 | SPRING PIN | Secures pump alignment dowels |
| 0730300820 | THRUST WASHER | Controls axial clearance in pump stack |
| 4482360002 | AXLE BEVEL GEAR | Transfers power to wheel hubs |
| 2095309081 | DIFFERENTIAL AXLE | Connects differential to final drive |
| 5838300811 | THRUST WASHER | Reduces friction in gear mesh |
| 4482360001 | DIFFERENTIAL BEVEL GEAR | Primary gear within differential assembly |
