Overview
The ZF 4660.273.020 COUPLING is a critical driveline component engineered specifically for the WG 92 and WG 98 transmission series. This OEM genuine part serves as the primary torque-transfer interface between the engine output and the transmission input shaft, ensuring smooth power delivery and vibration dampening during heavy-duty operations. Positioned within the bell housing assembly, this coupling works in concert with the 4660101020: TRANSMISSION HOUSING and the 4660301056: HOUSING II to maintain precise alignment and load distribution. The SKU 4660.273.020 is manufactured to ZF’s exacting tolerances, making it a direct replacement for worn units in WG 98 series transmissions.
Symptoms of Failure
- Torque converter shudder during acceleration: A worn 4660.273.020 coupling causes noticeable vibration or shudder when shifting from first to second gear, particularly under load.
- Transmission fluid contamination with metallic debris: As the coupling splines degrade, fine metal particles enter the hydraulic circuit, often detected during routine oil analysis or filter inspections.
- Intermittent gear engagement delays: A failing coupling allows excessive axial play, leading to delayed or harsh engagement when selecting forward or reverse gears.
- Audible clunking from the bell housing area: Loose or fractured coupling components produce a distinct metallic clunk during throttle tip-in or deceleration, indicating imminent failure.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4660.273.020 |
| Outer Diameter | 180 mm (7.09 in) |
| Inner Diameter (Spline) | 45 mm (1.77 in) |
| Overall Length | 95 mm (3.74 in) |
| Material | Heat-treated alloy steel (40CrMo4) |
| Weight | 2.8 kg (6.17 lbs) |
| OEM Reference | ZF 4660.273.020 |
| Surface Treatment | Phosphate coating for corrosion resistance |
Compatibility
This coupling is designed for ZF WG 92 and WG 98 series transmissions, including the WG180, WG200, and WG210 models commonly found in municipal trucks, refuse vehicles, and medium-duty construction equipment. It also fits select WG 98 variants used in fire apparatus and airport ground support vehicles. Always verify the transmission serial number against the OEM parts catalog before installation. The coupling interfaces directly with the 0631306174: CYLINDRICAL PIN for alignment and the 0769123894: TYPE PLATE for identification purposes.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4660101020 | TRANSMISSION HOUSING | Encloses and supports all internal transmission components |
| 4660301056 | HOUSING II | Secondary housing section for valve body and clutch packs |
| 0631306174 | CYLINDRICAL PIN | Precision alignment pin for coupling-to-housing fitment |
| 0769123894 | TYPE PLATE | Identification plate with transmission model and serial number |
| 0750100022 | SCREW PLUG | Seals hydraulic test ports and drain holes |
| 4660221031 | SUCTION TUBE | Transfers oil from pan to pump inlet |
| 0634100317 | O-RING | Static seal for housing joint faces |
| 0636103273 | CAP SCREW | Fastener for coupling-to-hub attachment |
| 0634306311 | O-RING | Dynamic seal for rotating shaft interface |
| 4660321029 | FIXING PLATE | Retains coupling axial position within housing |
