Overview
The ZF 4699.004.102 GK25 is a precision-engineered gear kit designed for the upper planetary assembly in heavy-duty ZF transmissions used in construction machinery. This OEM genuine part, identified by SKU 4699.004.102, directly controls the torque multiplication and speed reduction within the transmission’s final drive stage. It sits between the main housing and the output shaft, converting hydraulic motor power into mechanical rotation for the wheels or tracks. When paired with a robust 4699101043: HOUSING, this kit ensures seamless power delivery under extreme loads.
Symptoms of Failure
When the 4699.004.102 gear set begins to degrade, operators often notice specific performance drops. Look for these failure indicators to catch wear early:
- Grinding noise during gear engagement – A high-pitched whine or grinding sound from the transmission, especially under load, signals worn gear teeth.
- Intermittent power loss – The machine may hesitate or lose traction on inclines, indicating the gear set is slipping within the planetary carrier.
- Metal debris in transmission fluid – Fine metallic particles or larger chips in the oil filter or drain plug point directly to gear surface fatigue.
- Overheating near the final drive – Excessive friction from a failing gear kit can cause localized heat buildup, often accompanied by burnt oil smell.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4699.004.102 |
| Type | GK25 Gear Kit (Planetary) |
| Material | Case-hardened alloy steel (20MnCr5) |
| Weight | 4.2 kg (9.3 lbs) |
| Outer Diameter | 145 mm |
| Tooth Count | 23 (sun gear) / 41 (planet gears) |
| OEM Reference | ZF 4699.004.102 |
| Operating Temperature | -20°C to +120°C |
Compatibility
This gear kit is specifically engineered for ZF’s WG series powershift transmissions. It is a direct replacement for the following models:
- ZF WG180 – Used in wheel loaders and telehandlers (2010–2020)
- ZF WG200 – Common in articulated dump trucks and graders
- ZF WG210 – Found in heavy excavators and crawler dozers
- ZF WG250 – High-torque variants for mining equipment
Always verify the serial number on your transmission housing. The 4699102063: INPUT shaft and 4699103026: OUTPUT flange must be inspected for wear when replacing this gear kit. Additionally, the 4699105044: TURNTABLE BEARING should be replaced simultaneously to prevent premature failure of the new gears.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4699101043 | HOUSING | Encloses the planetary gear set; provides structural support |
| 4699102063 | INPUT | Transfers torque from the torque converter to the gear set |
| 4699103026 | OUTPUT | Connects the gear set to the final drive axle |
| 4699105044 | TURNTABLE BEARING | Supports rotational load between housing and output shaft |
| 4699301106 | HOUSING | Alternate housing variant for WG200 transmissions |
| 4699301015 | HOUSING COVER | Seals the top of the gear housing; prevents contamination |
| 4699301085 | COVER | Protects the input shaft from debris ingress |
| 4699301014 | THREAD PROTECTIVE SHIELD | Guards bolt threads during assembly and disassembly |
| 0634303980 | O-RING | Provides hydraulic seal between housing and cover |
| 0734307407 | PROTECTION CAP | Prevents dirt entry into unused ports during storage |
