Overview
The ZF 4699.804.106 GK25 is a precision-engineered gear set component designed for the upper power flow path in heavy-duty ZF transmissions used in construction machinery. This OEM genuine part, identified by SKU 4699.804.106, sits within the planetary gear assembly of the transmission, specifically managing torque distribution between the input shaft and the output drive. It is a critical wear item that ensures smooth engagement under high-load conditions, such as those found in wheel loaders and excavators. When paired with the 4699004015: GK25 unit, this component forms the core of the gear train, directly influencing operational efficiency and machine uptime.
Symptoms of Failure
When the ZF 4699.804.106 GK25 begins to degrade, operators typically notice these specific failure indicators:
- Intermittent gear slipping under load: The transmission may hesitate or lose torque when climbing grades or digging, often misdiagnosed as a clutch issue.
- Metallic grinding noise from the transmission housing: A distinct whine or chatter during gear shifts, particularly in forward-reverse cycles, signals worn gear teeth.
- Contaminated transmission fluid with metallic particles: Oil analysis reveals high iron content, indicating accelerated wear of the GK25 gear set.
- Delayed engagement or harsh shifting: The machine may lurch or take longer to respond when selecting a gear, pointing to internal gear mesh degradation.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 4699.804.106 |
| Material | Case-hardened alloy steel (20MnCr5 equivalent) |
| Weight | 3.2 kg (7.05 lbs) |
| Outer Diameter | 145 mm |
| Internal Spline Count | 24 teeth |
| OEM Reference | ZF 4699.804.106 (Genuine) |
| Heat Treatment | Carburized & tempered to HRC 58-62 |
Compatibility
This genuine ZF GK25 gear set is engineered for use in the following ZF transmission models commonly found in construction machinery:
- ZF WG180 – Used in mid-size wheel loaders (e.g., 3-5 ton class).
- ZF WG200 – Applied in heavy excavators and telehandlers.
- ZF WG120 – Found in compact construction equipment.
- ZF WG150 – Common in articulated dump trucks.
During installation, it is essential to inspect the 4699101025: HOUSING for cracks or wear, as housing distortion can accelerate gear failure. Additionally, the 4699102063: INPUT shaft and 4699103026: OUTPUT flange must be checked for spline wear to ensure proper alignment with the GK25 gear set.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4699004015 | GK25 | Primary gear set for torque multiplication |
| 4699101025 | HOUSING | Encloses and supports the gear assembly |
| 4699102063 | INPUT | Transfers engine power to the gear train |
| 4699103026 | OUTPUT | Delivers rotational force to the driveline |
| 4699105045 | TURNTABLE BEARING | Supports axial and radial loads in rotating assemblies |
| 4699301078 | HOUSING | Secondary housing for auxiliary gear sets |
| 4699301015 | HOUSING COVER | Seals the housing and retains lubricant |
| 4699301085 | COVER | Protects internal components from debris |
| 4699301014 | THREAD PROTECTIVE SHIELD | Prevents thread damage during assembly |
| 0634303980 | O-RING | Provides hydraulic seal between mating surfaces |
