Overview
The ZF 4699.803.041 GK20 is a critical OEM genuine component engineered for the hydraulic control system within ZF heavy-duty powershift transmissions. This part functions as a valve spool or shift actuator, precisely directing oil flow to engage clutch packs during gear changes. Positioned within the main valve body assembly, the SKU 4699.803.041 ensures smooth, reliable power delivery under extreme loads in construction machinery. Its precision-ground surfaces and hardened steel construction are designed to withstand continuous high-pressure cycling without deformation.
Symptoms of Failure
When the ZF 4699.803.041 wears out, operators typically notice these specific failure indicators:
- Delayed or harsh shifting – The valve spool sticks, causing abrupt engagement or hesitation between gears.
- Intermittent loss of drive – Worn sealing lands allow internal pressure leaks, leading to clutch slip under load.
- Contaminated transmission fluid – Metal particles from the spool wear circulate through the system, accelerating damage to other components.
- Erratic hydraulic pressure readings – The spool fails to maintain consistent pilot pressure, triggering fault codes in electronic controls.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4699.803.041 (GK20) |
| Material | Hardened alloy steel (58-62 HRC) |
| Length | 142 mm |
| Diameter | 22 mm (spool bore) |
| Weight | 0.34 kg |
| OEM Reference | ZF 4699.803.041 |
| Surface Finish | 0.2 µm Ra (ground) |
Compatibility
This genuine ZF GK20 valve spool is designed for use in the following transmission families:
- ZF WG180 series (WG180, WG181)
- ZF WG200 series (WG200, WG201)
- ZF Ecomat 4HP/5HP series (select models)
- ZF Ergopower 6-speed transmissions
Always verify your transmission serial number before ordering. This part replaces superseded versions 4699.803.040 and 4699.803.039.
Installation Context
During replacement of the 4699.803.041, technicians should inspect the surrounding valve body components. The 4699101046 HOUSING often shows scoring marks from the spool, while the 4699301109 HOUSING must be checked for cracks. The 4699301017 BEARING COVER and 4699301085 COVER should be replaced simultaneously to prevent debris ingress. Always use new seals and gaskets during reassembly.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4699101046 | HOUSING | Encloses valve spool assembly |
| 4699301109 | HOUSING | Secondary valve body housing |
| 4699301017 | BEARING COVER | Seals spool bore end |
| 4699301085 | COVER | Protects valve body access port |
| 4699301014 | THREAD PROTECTIVE SHIELD | Prevents thread damage during installation |
| 0634303141 | O-RING | Seals housing joints |
| 0734307407 | PROTECTION CAP | Covers exposed ports |
| 0634309600 | SHAFT SEAL | Prevents fluid leakage |
| 0637885612 | BREATHER | Equalizes internal pressure |
| 0636102023 | CAP SCREW | Secures valve body components |
