ZF 4108.302.099 PLANET CARRIER | OEM Genuine Part

Overview

The ZF 4108.302.099 PLANET CARRIER is a critical rotating assembly within the planetary gear set of heavy-duty construction machinery transmissions. This OEM genuine part functions as the central hub that supports the planetary gears, transferring torque from the sun gear to the ring gear while managing immense radial and axial loads. Positioned directly inside the main transmission housing, the planet carrier (SKU: 4108.302.099) ensures smooth power distribution during low-speed, high-torque operations typical of wheel loaders, graders, and dozers. When this component fails, the entire gear train loses structural integrity, leading to catastrophic transmission damage.

Symptoms of Failure

• Metallic grinding noise during gear engagement: Worn planet carrier bearings or cracked carrier arms produce a distinct grinding sound, especially when shifting from forward to reverse under load.
• Intermittent gear slipping under heavy load: A fatigued carrier allows planetary gears to misalign, causing the transmission to momentarily lose power when climbing grades or digging.
• Contaminated transmission fluid with metal shavings: As the carrier wears, microscopic steel particles enter the oil, visible during routine fluid changes as a “glitter” effect in the sump.
• Vibration through the driveline at low RPM: An unbalanced or warped planet carrier induces rhythmic shaking in the chassis, worsening as the transmission heats up.

Technical Specifications

Compatibility

This planet carrier is engineered for ZF’s WG-series powershift transmissions commonly used in construction machinery. It is a direct fit for the WG180 and WG200 transmission models, as well as the heavy-duty WG220 variant. The carrier also appears in certain 4WG-200 and 5WG-200 configurations. Always verify your transmission serial number before ordering, as minor design revisions exist between early and late production runs.

Installation Context

When replacing the 4108.302.099 planet carrier, it is essential to inspect the surrounding components for wear. The carrier sits inside the 4108101112: HOUSING, which must be free of cracks or scoring. The 4108201177: HOUSING provides the outer race for the planetary gears and should be replaced if pitted. Use a new 0636302056: SCREW PLUG to seal the carrier’s lubrication port, and install a fresh 4108301304: BEARING COVER to prevent debris ingress. For complete rebuilds, also consider the 4108306173: GASKET and 0750110040: SHAFT SEAL to ensure a leak-free assembly.

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