ZF 4644.303.123 BUSH for WG160/WG180/WG190 | OEM Genuine Part

Overview

This genuine OEM ZF 4644.303.123 BUSH serves as a critical wear component within the planetary gearset assembly of heavy-duty WG-series transmissions. Designed to reduce friction between rotating shafts and stationary housings, this bushing maintains precise axial alignment under high torque loads. The SKU 4644.303.123 is engineered to fit seamlessly into the lubrication circuit, ensuring consistent oil film distribution across mating surfaces. When installed alongside a TRANSMISSION HOUSING or a TRANSMISSION HOUSING, this bushing provides the foundational support necessary for smooth gear engagement and extended service intervals.

Symptoms of Failure

• Low-frequency whining noise during acceleration: A worn 4644.303.123 bushing allows radial play, causing metallic contact that generates a distinct humming sound under load.
• Intermittent gear slippage in higher ranges: As the bushing degrades, shaft misalignment disrupts hydraulic clutch pack engagement, particularly noticeable in WG180 and WG190 units.
• Dark metallic particles in transmission fluid: Bearing surface erosion releases bronze or steel debris into the oil, often visible during routine drain inspections.
• Oil seepage around the output shaft seal area: Excessive bushing clearance can distort the seal lip, leading to gradual fluid loss and eventual contamination.

Technical Specifications

Compatibility

This bushing is engineered for direct fitment in ZF WG160, WG180, WG190, WG200, and WG210 series transmissions. It is commonly used in the countershaft support bore and reverse idler gear positions. For proper assembly, always pair this part with a GROOVED STUD to secure the housing alignment, and verify the TYPE PLATE identification to confirm your exact transmission variant. While primarily designed for WG180 and WG190 models, the 4644.303.123 also serves as a direct replacement in earlier WG160 units and later WG200/WG210 upgrades.

Related Components

Frequently Asked Questions

Q: How do I know if the 4644.303.123 bushing is the correct size for my WG180?
A: Measure the shaft journal diameter at the bushing contact point. The inner diameter of this bushing is 38.10 mm. If your shaft measures within 38.05–38.15 mm, this part is compatible. Always cross-reference with your TYPE PLATE for model confirmation.

Q: Can I reuse the old bushing if I replace the transmission housing?
A: No. The bushing wears to match the original shaft surface profile. Installing a used bushing into a new TRANSMISSION HOUSING will cause accelerated wear and potential misalignment. Always install a new 4644.303.123 bushing with any housing replacement.

Q: What torque should I apply to the GROOVED STUD when securing this bushing?
A: The grooved stud should be hand-tightened to 15 Nm (11 ft-lbs) using a torque wrench. Overtightening can distort the bushing bore and cause premature failure. Always lubricate the stud threads with clean transmission fluid before installation.