Overview
The ZF 4699.803.016 GK20 is a genuine OEM component engineered for the internal lubrication and cooling circuits within ZF heavy-duty powershift transmissions. This part functions as a critical fluid director, ensuring consistent oil pressure to clutches and planetary gear sets. Designated as SKU 4699.803.016, it is precision-machined to maintain the exact flow characteristics required for high-torque construction machinery applications. Typically located in the lower valve body or main control housing assembly, this component works in direct conjunction with the 4699101024 HOUSING to seal and route hydraulic fluid without cross-contamination.
Symptoms of Failure
- Erratic clutch engagement during cold starts: When the 4699.803.016 wears, internal bypass leakage causes delayed or harsh shifting, particularly in low ambient temperatures.
- Visible oil seepage at the transmission bell housing: Cracks or deformation in this part lead to external fluid loss, often mistaken for a main seal failure.
- Transmission overheating under load: Reduced flow through the cooler circuit due to internal wear of the GK20 results in elevated sump temperatures during excavation or grading operations.
- Intermittent gear slip in forward ranges: A worn fluid director fails to maintain pressure to the forward clutch pack, causing momentary power loss under heavy load.
Technical Specifications
| Part Number | 4699.803.016 |
| Designation | GK20 Fluid Director / Flow Control Insert |
| Material | Hardened Aluminum Alloy (EN AW-6082) with Anodized Coating |
| Weight | 0.34 kg (0.75 lbs) |
| Overall Length | 82.5 mm |
| Outer Diameter | 38.0 mm |
| O-Ring Groove | 2.5 mm x 1.5 mm (for 0634303141) |
| OEM Reference | ZF 4699.803.016 (Genuine) |
| Operating Pressure | 18-22 bar (261-319 psi) |
Compatibility
This genuine GK20 fluid director is designed for use in the following ZF transmission families commonly found in wheel loaders, graders, and telehandlers:
- ZF WG180 (all series)
- ZF WG200 (all series)
- ZF WG210 (early production)
- ZF 4WG-200 / 4WG-210
During installation, always inspect the mating surfaces of the 4699301077 HOUSING for scoring or burrs. The 4699301017 BEARING COVER must be torqued to specification to prevent distortion of the GK20 bore. Additionally, the 4699301085 COVER should be replaced simultaneously to ensure proper sealing of the valve body cavity.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4699101024 | HOUSING | Main transmission housing, supports gear train and valve body |
| 4699301077 | HOUSING | Intermediate housing for clutch pack assembly |
| 4699301017 | BEARING COVER | Seals and preloads output shaft bearing |
| 4699301085 | COVER | Valve body access cover with gasket surface |
| 4699301014 | THREAD PROTECTIVE SHIELD | Protects housing threads during assembly |
| 0634303141 | O-RING | Seals fluid director to housing bore |
| 0734307407 | PROTECTION CAP | Covers unused hydraulic ports during transport |
| 0634319161 | SHAFT SEAL | Prevents oil leakage at rotating shaft interface |
| 0637885612 | BREATHER | Equalizes internal transmission pressure |
| 0636102023 | CAP SCREW | M10x1.5 fastener for housing attachment |
