Overview
The ZF 4661.203.001 OUTPUT FLANGE is a critical driveline component engineered for the WG90 and WG94 series transmissions. This OEM genuine part serves as the primary interface between the transmission output shaft and the driveshaft, transferring rotational torque from the gearset to the vehicle’s wheels. Positioned at the rear of the transmission housing, the output flange is splined to the output shaft and sealed against the TRANSMISSION HOUSING to maintain lubrication integrity. The SKU 4661.203.001 is precision-machined to ZF’s original specifications, ensuring a direct bolt-on replacement without modifications.
Symptoms of Failure
- Transmission fluid leak at the rear output seal: A worn output flange often damages the sealing surface, causing oil to drip from the rear of the transmission bell housing. This is a common long-tail search query for “ZF WG90 output flange oil leak.”
- Driveshaft vibration or wobble: Excessive play in the flange splines or a bent flange face leads to driveline imbalance, felt as a rhythmic vibration during acceleration.
- Clunking noise on gear engagement: Worn splines on the 4661.203.001 flange create backlash, producing a metallic clunk when shifting from Park to Drive or Reverse.
- Difficulty removing the driveshaft: Corrosion or galling on the flange pilot diameter can cause the driveshaft to seize, requiring forceful extraction during service.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (OEM) | 4661.203.001 |
| Material | High-tensile steel, induction-hardened |
| Outer Diameter | 180 mm (7.09 in) |
| Pilot Diameter | 65 mm (2.56 in) |
| Bolt Hole Circle | 150 mm (5.91 in) – 6 holes |
| Spline Count | 24 internal splines |
| Weight | 3.2 kg (7.05 lbs) |
| OEM Reference | ZF 4661.203.001 |
| Seal Surface Finish | Ra 0.4 µm (ground) |
Compatibility
This output flange is designed for the ZF WG90 and WG94 series transmissions, which are commonly found in medium-duty trucks, buses, and off-highway equipment. Based on the spline geometry and bolt pattern, the 4661.203.001 is also compatible with select WG180 and WG200 variants that share the same output shaft interface. Always verify the spline count and pilot diameter against your existing flange before installation. The flange mounts directly to the output shaft within the HOUSING assembly, and the CYLINDRICAL PIN is used to align the flange during assembly. A TUBE may also be present in the housing to direct oil flow to the flange bearings.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4661101001 | TRANSMISSION HOUSING | Main structural casing enclosing the gearset and output shaft |
| 4661301007 | HOUSING | Rear housing section supporting the output flange and bearings |
| 4661301093 | TUBE | Oil delivery tube for lubrication of the output shaft area |
| 0631306174 | CYLINDRICAL PIN | Alignment pin for precise flange-to-shaft positioning |
| 0769123894 | TYPE PLATE | Identification plate riveted to the transmission housing |
| 0750100022 | SCREW PLUG | Sealing plug for oil drain or inspection ports |
| 0636302602 | SCREW PLUG | Magnetic drain plug for ferrous debris collection |
| 0634100633 | O-RING | Seal between the output flange and housing bore |
| 4661301029 | NOZZLE | Lubrication nozzle for the output shaft bearing |
| 4661301027 | NOZZLE | Secondary oil nozzle for gear cooling |
