Overview
The ZF 4657.026.123 6 WG 190 Powershift Transmission Assembly | Complete Unit is a fully integrated, factory-matched gearbox core designed for heavy-duty off-highway machinery. This complete assembly serves as the central power transfer module within the WG 190 series, converting engine torque into controlled hydraulic and mechanical drive. The SKU 4657.026.123 represents a remanufactured or new-build unit that includes the main gear cluster, clutch packs, and valve body. It sits directly between the engine bellhousing and the final drive, with the TRANSMISSION HOUSING forming its structural backbone. For a full rebuild, this unit must be paired with the HOUS.FRONT SECT and the HOUSING REAR PART to ensure proper alignment of all rotating elements.
Symptoms of Failure
When the ZF 4657.026.123 assembly begins to fail, operators will notice distinct performance degradation. Delayed engagement or gear slipping under load is the most common complaint, often accompanied by erratic shift patterns. Internal hydraulic pressure loss leads to weak clutch pack clamping, causing the transmission to overheat during sustained operation. Metallic debris in the oil pan indicates bearing or gear tooth wear, while audible whining or grinding noises from the housing suggest imminent failure of the planetary gear set. If you observe any of these symptoms, inspect the HOUSING REAR SECTION for cracks or warping that could compromise oil sealing.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number / SKU | 4657.026.123 |
| Series | WG 190 (6-speed powershift) |
| Overall Length | ~820 mm (estimated) |
| Dry Weight | ~285 kg (complete unit) |
| Housing Material | High-grade cast iron (GGG-40) |
| Max Input Torque | 1,900 Nm |
| OEM Reference | ZF 6 WG 190 |
| Bolt Torque (housing) | 120 Nm (M12 cap screws) |
Compatibility
This complete assembly is engineered for the ZF WG 190 series powershift transmissions. It is directly compatible with the WG 180 and WG 200 models when using the appropriate adapter plates, though internal gear ratios may differ. The unit also fits select WG 160 variants with housing modifications. Always verify the bellhousing pattern against your existing TRANSMISSION HOUSING before installation. For mixed-series applications, the HOUS.FRONT SECT and HOUSING REAR PART must match the original transmission generation to avoid spline misalignment.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4657101082 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4657201166 | HOUS.FRONT SECT | Front section housing input shaft |
| 4657201170 | HOUSING REAR PART | Rear section supporting output flange |
| 4657298102 | HOUSING REAR SECTION | Alternate rear housing variant |
| 0631306816 | CYLINDRICAL PIN | Alignment dowel for housing halves |
| 0636100801 | CAP SCREW | M12 bolt for housing fastening |
| 4656301148 | FIXING PLATE | Locks bearing preload adjustment |
| 4657301032 | SCREEN SHEET | Fine mesh filter for oil circuit |
| 4657301033 | SCREEN SHEET | Coarse mesh pre-filter |
| 0636100803 | CAP SCREW | M10 bolt for valve body mounting |
