ZF 4108.121.020 FILTER for WG100/WG130/WG131 | OEM Genuine Part

Overview

The ZF 4108.121.020 FILTER is a critical component engineered for the lubrication and hydraulic circuits of the WG100, WG130, and WG131 transmission series. This OEM genuine part ensures that transmission fluid remains free of particulate contaminants, directly protecting internal valve bodies and clutch packs from abrasive wear. As a primary line of defense in the oil circulation loop, the 4108.121.020 filter sits within the main sump or external filtration housing, maintaining the fluid cleanliness required for consistent shift quality. When servicing the filtration system, it is standard practice to inspect the 4108101140: HOUSING for cracks or seal degradation, as the housing provides the structural seat for this filter element.

Symptoms of Failure

• Delayed or harsh gear engagement: A clogged 4108.121.020 filter restricts oil flow, causing slow clutch pack fill times and abrupt shifts, especially during cold starts.
• Transmission overheating: When the filter becomes saturated with debris, the lubrication circuit loses efficiency, leading to elevated sump temperatures and potential thermal damage.
• Whining or cavitation noise from the pump: A blocked filter starves the hydraulic pump of fluid, producing a high-pitched whine as the pump struggles to draw oil through the restriction.
• Visible metallic debris in the oil pan: If the filter media fails or bypasses, fine metal particles will accumulate in the pan, often accompanied by erratic shifting behavior.

Technical Specifications

Compatibility

This filter is designed for ZF WG series transmissions, specifically the WG100, WG130, and WG131 models. It is also compatible with certain variants of the WG180 and WG200 series where the same filtration housing is used. Always verify the housing condition by checking the 0501211694: MOTOR assembly for proper alignment, as the motor drives the pump that circulates oil through this filter. Additionally, the 0501314793: COVER must be torqued correctly to prevent leaks, and the 0501314799: BUSH should be inspected for wear to avoid lateral play in the pump shaft.

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