Overview
The ZF 8607.955.102 RAD.PISTON PUMP is a critical hydraulic component engineered specifically for the WG 65 series transmission. This OEM genuine part functions as the primary pressure source for the transmission’s hydraulic control system, delivering precise oil flow to actuate clutch packs and valve bodies. Located within the transmission housing, the pump draws fluid from the sump and pressurizes it to ensure smooth gear engagement and torque converter operation. The SKU 8607.955.102 is manufactured to ZF’s exacting tolerances, guaranteeing reliable performance in heavy-duty industrial applications where consistent hydraulic pressure is non-negotiable.
Symptoms of Failure
- Intermittent gear slipping under load: When the RAD.PISTON PUMP loses volumetric efficiency, the transmission may exhibit delayed or erratic shifting, particularly during uphill hauling or high-torque operations.
- Low hydraulic pressure warnings: A worn pump often triggers dashboard pressure alerts or diagnostic trouble codes (DTCs) indicating insufficient system pressure, leading to clutch chatter.
- Oil aeration and foaming: Internal wear in the 8607.955.102 can introduce air into the hydraulic circuit, causing spongy shift feel and visible bubbles in the transmission fluid dipstick.
- Persistent oil leaks near the pump housing: Seal degradation around the pump mounting point results in fluid seepage, often mistaken for a TRANSMISSION HOUSING crack.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 8607.955.102 |
| Pump Type | Radial Piston |
| Displacement | 12.5 cc/rev (estimated) |
| Maximum Pressure | 25 bar (363 psi) |
| Material | Hardened steel rotor with aluminum housing |
| Weight | 2.8 kg (6.2 lbs) |
| OEM Reference | ZF 8607.955.102 |
| Seal Type | PTFE lip seal |
Compatibility
This RAD.PISTON PUMP is designed for the ZF WG 65 series, but its hydraulic architecture also supports select models in the WG180, WG200, and WG250 families when used with the correct OUTPUT shaft configuration. The pump interfaces directly with the OUTPUT FLANGE to drive the hydraulic circuit. Always verify the mounting bolt pattern using the HEXAGON SCREW specifications before installation. For WG65 applications, this part is a direct OEM replacement requiring no modifications.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4616105413 | OUTPUT | Transfers torque from pump to driveline |
| 4616203017 | OUTPUT FLANGE | Connects output shaft to universal joint |
| 4616101117 | TRANSMISSION HOUSING | Encloses pump and gear assembly |
| 0636011038 | HEXAGON SCREW | Secures pump mounting bracket |
| 0636016015 | HEXAGON SCREW | Fastens output flange to shaft |
| 0631306085 | CYLINDRICAL PIN | Aligns pump housing during assembly |
| 0634313118 | O-RING | Seals pump inlet port |
| 0732611049 | FILTER INSERT | Captures debris before pump intake |
| 0634303718 | O-RING | Seals pump outlet port |
| 0636610082 | STUD | Positions pump on housing flange |
