Overview
The ZF 0501.298.376 PISTON is a critical hydraulic actuation component engineered for the WG100, WG130, and WG131 transmission series. This OEM genuine part converts hydraulic pressure into precise mechanical force to engage clutch packs and shift gears within the transmission valve body. As a precision-machined component, the 0501.298.376 piston ensures consistent oil flow regulation and pressure sealing. When paired with the 4108101153 HOUSING, it forms a sealed hydraulic circuit that controls gear engagement timing. The SKU 0501.298.376 is manufactured to ZF’s original tolerances, guaranteeing direct fitment without modification.
Symptoms of Failure
- Delayed or harsh gear engagement – A worn piston fails to maintain hydraulic pressure, causing noticeable hesitation or jarring shifts when accelerating from a stop.
- Internal transmission oil leaks – Degraded piston seals allow ATF to bypass the cylinder, resulting in low fluid levels and visible drips under the vehicle.
- Slipping in forward or reverse gears – Insufficient piston stroke prevents full clutch pack clamping, leading to RPM flare without corresponding vehicle movement.
- Erratic shift timing – The piston’s inability to hold steady pressure causes unpredictable upshifts or downshifts, particularly under load.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 0501.298.376 |
| Material | Hardened alloy steel with nitrided surface |
| Outer Diameter | 42.5 mm |
| Inner Diameter | 28.0 mm |
| Height | 34.2 mm |
| Weight | 0.185 kg |
| OEM Reference | ZF 0501.298.376 |
| Seal Type | Integrated PTFE lip seal |
Compatibility
This piston is specifically designed for ZF WG-series transmissions used in industrial and agricultural machinery. Verified compatible models include:
- ZF WG100
- ZF WG130
- ZF WG131
It may also function in WG180 and WG200 variants with identical piston bore dimensions, though cross-referencing with the 0501212152 MOTOR and 0501314793 COVER is recommended to confirm assembly compatibility. The 0735370299 TAPERED ROLLER BEARING often requires replacement during the same service interval to prevent premature piston wear.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4108101153 | HOUSING | Encloses piston assembly and directs oil flow |
| 0501212152 | MOTOR | Hydraulic drive unit for piston actuation |
| 0501314793 | COVER | Seals the piston chamber and retains pressure |
| 0735370299 | TAPERED ROLLER BEARING | Supports rotating shaft loads near piston assembly |
| 0501317874 | HOUSING | Secondary housing for auxiliary piston circuits |
| 0501317875 | ROLLER | Reduces friction in piston guide channels |
| 0501317876 | COMPRESSION SPRING | Returns piston to neutral position |
| 0501314823 | BUSH | Wear sleeve for piston rod interface |
| 0501314929 | CAM DISC | Timing control for piston stroke sequence |
| 0501318668 | HOUSING | Lower housing for piston return spring assembly |
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