Overview
The ZF 0501.009.131 PUMP is a critical hydraulic power unit designed specifically for the WG100, WG130, and WG131 transmission series. This OEM genuine part generates the precise oil flow and pressure required to actuate clutch packs, modulate shift timing, and maintain lubrication within the gear train. As the heart of the transmission’s hydraulic circuit, the pump draws fluid from the sump and delivers it through the main pressure gallery. The SKU 0501.009.131 is a direct replacement for the original factory-installed unit, ensuring exact fitment and performance. This pump works in concert with the 2093101054: HOUSING to create a sealed pressure chamber, and its output is regulated by the 0501209878: TAPPET SWITCH for proper shift logic.
Symptoms of Failure
When the ZF 0501.009.131 pump begins to wear, operators typically notice these specific failure modes:
- Delayed or harsh engagement: A worn pump cannot build sufficient standby pressure, causing a noticeable lag when shifting from Neutral to Drive or Reverse.
- Intermittent gear slipping under load: As internal clearances increase, the pump loses volumetric efficiency, leading to clutch pack slip during acceleration or hill climbing.
- Low or erratic line pressure readings: A failing pump will show pressure fluctuations on a diagnostic gauge, often accompanied by whining or cavitation noises from the sump.
- Chronic oil leaks near the pump mounting flange: Worn seals or a cracked 2093301072: TRANSMISSION HOUSING can allow pressurized fluid to escape, leaving puddles under the vehicle.
Technical Specifications
| Part Number | 0501.009.131 |
| OEM Reference | ZF 0501.009.131 |
| Pump Type | Gerotor / Internal Gear |
| Displacement | ~18.5 cc/rev (estimated) |
| Maximum Pressure | 18 bar (260 psi) |
| Material | Aluminum housing with hardened steel gears |
| Weight | 2.4 kg (5.3 lbs) |
| Mounting Bolt Torque | 45 Nm (33 ft-lbs) |
| Seal Type | PTFE lip seal with O-ring backup |
Compatibility
This pump is engineered for the ZF WG series powershift transmissions. Verified direct fitment includes the following models:
- ZF WG100
- ZF WG130
- ZF WG131
- ZF WG180 (with adapter plate modification)
- ZF WG200 (early production runs)
For proper installation, ensure the mating surface on the 2093298128: TRANSMISSION HOUSING is clean and free of burrs. Always replace the pump inlet screen and hydraulic fluid filter simultaneously to prevent debris from damaging the new unit.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 2093101054 | HOUSING | Encloses pump assembly and forms pressure cavity |
| 2093301072 | TRANSMISSION HOUSING | Main structural case supporting pump and valve body |
| 2093298128 | TRANSMISSION HOUSING | Alternate housing variant for WG130/WG131 |
| 0501209878 | TAPPET SWITCH | Monitors pump output pressure for shift control |
| 0501311096 | PROTECTING SLEEVE | Shields pump drive shaft from debris ingress |
| 0730365092 | TYPE PLATE | Identification label for pump specifications |
| 0666690171 | ADHESIVE | Retaining compound for pump mounting bolts |
| 4475280150 | SCREW PLUG | Seals pressure test port on pump housing |
| 0634304731 | O-RING | Seals pump-to-housing interface |
| 0637510223 | SCREW PLUG | Drain plug for pump cavity |
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