Overview
The ZF 4699.803.088 GK20 is a precision-engineered gear set assembly designed for the power-dense GK20 transmission series. This OEM genuine part functions as the primary reduction stage within the gearbox, converting high-speed input torque from the engine into usable, high-torque output for demanding construction machinery. The SKU 4699.803.088 is a direct replacement component, ensuring exact fitment and original ZF load ratings. It sits directly between the input shaft and the planetary carrier, making it a critical link in the drivetrain’s power flow.
Symptoms of Failure
When the 4699.803.088 gear set begins to wear, operators often notice distinct performance issues. Look for these specific failure symptoms:
- Whining or howling noise during acceleration: A high-pitched metallic sound from the transmission housing indicates gear tooth surface fatigue or pitting.
- Intermittent gear slipping under load: The machine may momentarily lose power when climbing or digging, as worn teeth fail to maintain proper mesh.
- Metal particles in the transmission oil filter: Flakes or slivers of steel found during routine maintenance confirm internal gear degradation.
- Vibration through the chassis at specific RPM ranges: Unbalanced gear wear creates harmonic oscillations that resonate through the driveline.
Technical Specifications
| Part Number | 4699.803.088 |
| Designation | GK20 Gear Set |
| Material | Case-hardened alloy steel (20MnCr5 equivalent) |
| Weight | 4.8 kg (10.6 lbs) |
| Outer Diameter | 185 mm |
| Tooth Count | 23 teeth (input) / 47 teeth (output) |
| OEM Reference | ZF 4699.803.088 |
Compatibility
This gear set is engineered for the ZF GK20 transmission family, commonly found in wheel loaders, telehandlers, and excavators. It is a direct fit for the following ZF models: WG180, WG200, WG211, and WG220. Always verify your transmission serial number before ordering, as minor revisions exist between early and late production units.
During installation, this 4699.803.088 gear set works in conjunction with the 4699003010: GK20 main assembly. The 4699101046: HOUSING provides the structural envelope, while the 4699102072: INPUT shaft delivers power into this gear set. The 4699103030: OUTPUT shaft then transfers the reduced speed to the final drive. Replacing all four components simultaneously is recommended to prevent premature wear from mismatched tolerances.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4699003010 | GK20 | Main transmission assembly |
| 4699101046 | HOUSING | Structural casing for gear set |
| 4699102072 | INPUT | Input shaft and spline |
| 4699103030 | OUTPUT | Output shaft and flange |
| 4699105010 | TURNTABLE BEARING | Rotary support bearing |
| 4699301109 | HOUSING | Secondary housing cover |
| 4699301017 | BEARING COVER | Seals and protects bearings |
| 4699301085 | COVER | Access cover for inspection |
| 4699301014 | THREAD PROTECTIVE SHIELD | Protects threaded bores |
| 0634303141 | O-RING | Hydraulic seal |
