ZF 4644.102.421 INPUT for WG200 | OEM Genuine Part

Overview

The ZF 4644.102.421 INPUT for WG200 is a critical driveline component engineered to transfer rotational force from the torque converter directly into the planetary gearset. Positioned at the front of the transmission housing, this OEM genuine input shaft absorbs high-torque loads during every shift cycle. The SKU 4644.102.421 is precision-machined to ZF’s original tolerances, ensuring a spline-fit that eliminates backlash. When replacing this input, it is standard practice to also inspect the 4644105414: DISCONNECTION mechanism, as both components share the same lubrication circuit and wear patterns.

Symptoms of Failure

• Hard shifting or delayed engagement – A worn input shaft spline causes the clutch pack to engage unevenly, producing a noticeable lag when moving from Neutral to Drive.
• Transmission oil leaks at the bell housing – Deterioration of the input shaft seal surface allows ATF to weep past the 4644101231: TRANSMISSION HOUSING interface, leaving puddles under the vehicle.
• Vibration during acceleration – Eccentric wear on the input shaft bearing journal creates a low-frequency shudder that intensifies under load.
• Metallic debris in the oil pan – Flaking from the hardened steel surface contaminates the hydraulic system, often requiring simultaneous replacement of the 4644303409: OUTPUT FLANGE to prevent cross-contamination.

Technical Specifications

Compatibility

This input shaft is specifically designed for the WG 200 Series transmissions, including the WG180, WG200, and WG210 variants used in municipal buses, fire trucks, and heavy-duty off-road equipment. It is not backward-compatible with the earlier WG150 series due to a different pilot bearing diameter. Always verify the transmission serial number against the ZF parts catalog before ordering.

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