Overview
The ZF 4699.803.033 GK20 is a precision-engineered gear assembly designed for the transfer case section of heavy-duty construction machinery transmissions. This OEM genuine part functions as a critical power distribution component, managing torque flow between the input shaft and the output drives. The SKU 4699.803.033 is specifically calibrated for ZF’s modular transmission architecture, ensuring seamless engagement under high-load conditions typical in excavators and wheel loaders. It sits within the intermediate housing, directly interfacing with the planetary gear set to regulate speed ratios during low-range operation.
Symptoms of Failure
- Intermittent gear slippage under load: When the 4699.803.033 wears, operators may notice sudden loss of drive power when climbing gradients or digging, often accompanied by a grinding noise from the transmission center housing.
- Metallic debris in hydraulic oil: Pitting on the GK20 gear teeth generates fine steel particles visible during routine oil sampling, indicating imminent failure of the 4699003018: GK20 assembly.
- Oil seepage at the housing joint: Worn thrust washers on this part cause axial play, leading to hydraulic fluid leaking past the 4699101046: HOUSING seal interface.
- Delayed engagement from neutral to drive: Degraded splines on the gear hub create a hesitation of 2-3 seconds before power transfers to the 4699102091: INPUT shaft.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4699.803.033 |
| Designation | GK20 Gear Kit |
| Outer Diameter | 185 mm |
| Inner Spline Diameter | 42 mm |
| Tooth Count | 23 (helical) |
| Material | Case-hardened 20MnCr5 steel |
| Weight | 3.8 kg |
| Surface Hardness | 58-62 HRC |
| OEM Reference | ZF 4699.803.033 |
Compatibility
This GK20 gear is compatible with ZF WG180, WG200, and WG250 series transmissions used in construction machinery from 2010 onward. It directly replaces the original equipment in the 4699103030: OUTPUT shaft cluster. The part also fits select models of the ZF 4WG-200 and 6WG-250 transfer cases where the gear ratio requires a 23-tooth helical profile. Always verify the housing casting number before installation, as the 4699301109: HOUSING variant may require different shim thicknesses.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4699003018 | GK20 | Primary gear reduction set |
| 4699101046 | HOUSING | Encloses gear cluster |
| 4699102091 | INPUT | Torque input shaft assembly |
| 4699103030 | OUTPUT | Drive output flange |
| 4699105010 | TURNTABLE BEARING | Rotary support bearing |
| 4699301109 | HOUSING | Transfer case housing |
| 4699301017 | BEARING COVER | Seals bearing cavity |
| 4699301085 | COVER | Inspection cover plate |
| 4699301014 | THREAD PROTECTIVE SHIELD | Prevents thread damage |
| 0634303141 | O-RING | Hydraulic seal |
