Overview
The ZF 4474.393.026 Crown Wheel is a critical hypoid ring gear engineered for the final drive assembly of heavy-duty construction machinery transmissions. This OEM genuine part, identified by SKU 4474.393.026, directly interfaces with the pinion gear to transfer rotational torque from the differential to the axle shafts. Precision-machined from forged alloy steel, it ensures smooth power delivery under extreme load conditions. As a genuine ZF component, it guarantees exact fitment and metallurgical integrity, eliminating the risk of premature failure associated with aftermarket alternatives. This crown wheel is specifically designed to handle the high shock loads and continuous operation typical of wheel loaders, graders, and dump trucks.
Symptoms of Failure
When the ZF 4474.393.026 crown wheel wears beyond tolerance, operators will notice distinct performance degradation. Recognizing these signs early can prevent catastrophic drivetrain damage.
- Howling or whining noise from the axle during acceleration: A high-pitched gear whine, particularly when turning or under load, indicates uneven tooth wear or pitting on the crown wheel surface.
- Vibration in the operator cab at low speeds: Excessive backlash between the crown wheel and pinion creates a rhythmic shudder felt through the floorboard, often mistaken for tire imbalance.
- Metallic debris in the differential oil: Flakes or silver particles found during routine oil changes confirm active spalling of the gear teeth, requiring immediate replacement.
- Intermittent drive engagement or “clunking”: A delayed or harsh engagement when shifting between forward and reverse signals that the gear tooth profile has been compromised.
Technical Specifications
| Part Number (SKU) | 4474.393.026 |
| Component Type | Hypoid Crown Wheel (Ring Gear) |
| Outside Diameter | 320 mm (estimated) |
| Number of Teeth | 41 (estimated) |
| Mounting Bolt Pattern | 12 x M14 bolts on 280 mm PCD |
| Material | Case-hardened alloy steel (20MnCr5 equivalent) |
| Weight | 8.2 kg (18.1 lbs) |
| OEM Reference | ZF 4474.393.026 (Genuine) |
| Surface Treatment | Shot-peened and phosphated |
Compatibility
This crown wheel is designed for integration into specific ZF heavy-duty transmission and axle series. It is primarily used in the final drive reduction stage of the following models:
- ZF WG180 series (Wheel Loader transmissions)
- ZF WG200 series (Grader and heavy truck transmissions)
- ZF AP400 series (Rigid dump truck axles)
- ZF TC-Tronic series (Telehandler applications)
Always verify the axle housing casting number and existing gear ratio before installation. This part is not interchangeable with crown wheels from the ZF Ecomat or AS Tronic series.
