Overview
The ZF 4108.302.173 PLANET CARRIER is a critical rotating assembly within the planetary gear set of heavy-duty construction machinery transmissions. This OEM genuine part serves as the structural hub that houses planetary gears, pins, and bearings, transferring torque from the input shaft to the output shaft while enabling the necessary gear reduction. Positioned directly within the transmission housing, the planet carrier must withstand extreme radial and axial loads during operation. The SKU 4108.302.173 is precision-machined to OEM tolerances, ensuring proper alignment with the 4108101108: HOUSING and the 4108301436: INPUT SHAFT for seamless power flow.
Symptoms of Failure
- Metallic grinding noise during gear engagement: Worn planet carrier bearing journals or cracked carrier arms cause uneven gear meshing, producing a distinct grinding sound when shifting under load.
- Intermittent transmission slipping under heavy load: A fatigued planet carrier can allow planetary gears to walk out of alignment, leading to sudden loss of torque transfer during excavation or lifting operations.
- Oil contamination with metallic debris: As the carrier surface wears, fine steel particles enter the hydraulic circuit, often visible on the 4108306172: GASKET sealing surfaces during inspection.
- Vibration at specific RPM ranges: Imbalanced carrier rotation due to uneven gear wear creates resonant vibrations that worsen over time, eventually damaging the 0730365280: TYPE PLATE mounting points.
Technical Specifications
| Part Number | 4108.302.173 |
| Material | High-tensile alloy steel (case-hardened) |
| Outer Diameter | 185 mm (approx.) |
| Overall Length | 95 mm (approx.) |
| Weight | 4.2 kg (9.3 lbs) |
| OEM Reference | ZF 4108.302.173 |
| Bearing Type | Needle roller (compatible with 0735330931: BALL BEARING) |
| Retaining Ring Spec | 0630532160: RETAINING RING and 0630531130: RETAINING RING |
| Sealing Components | 0636302014: SCREW PLUG, 0634801057: SEALING RING, 4475280018: SCREW PLUG |
Compatibility
This planet carrier is designed for ZF WG-series transmissions commonly used in wheel loaders, graders, and telehandlers. It is a direct fit for the WG180 and WG200 models, as well as the WG150 series in certain configurations. The 4108.302.173 also appears in select ZF 4WG-200 and ZF 6WG-250 power shift transmissions. Always verify the carrier spline count and bearing journal dimensions against your existing unit before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4108101108 | HOUSING | Encloses the planetary gear set and carrier assembly |
| 4108306172 | GASKET | Seals the housing-to-carrier interface to prevent oil leaks |
| 0730365280 | TYPE PLATE | Identification plate for transmission model and serial number |
| 4108301436 | INPUT SHAFT | Transfers engine torque to the planet carrier |
| 0735330931 | BALL BEARING | Supports carrier rotation within the housing |
| 0630532160 | RETAINING RING | Secures bearings on the carrier shaft |
| 0630531130 | RETAINING RING | Locks planetary gear pins in position |
| 0636302014 | SCREW PLUG | Closes oil passages in the carrier assembly |
| 0634801057 | SEALING RING | Prevents fluid bypass around the carrier hub |
| 4475280018 | SCREW PLUG | Seals threaded ports on the carrier body |
