Overview
The ZF 4657.026.307 6 WG 190 Powershift Transmission Assembly | Complete Unit is a fully assembled, drop-in ready gearbox core designed for heavy-duty off-highway machinery. This complete unit integrates the planetary gear sets, clutch packs, and hydraulic control system into a single, pre-tested assembly. As the central power transfer module, it sits between the engine and the final drive, managing torque distribution across six forward speeds. The SKU 4657.026.307 is a direct OEM replacement for the WG 190 series, ensuring precise fitment without modification. When rebuilding a transmission, this assembly must be paired with a robust TRANSMISSION HOUSING to protect internal components from debris and structural stress.
Symptoms of Failure
- Erratic gear engagement or slipping under load: Worn clutch discs or piston seals inside the assembly cause delayed shifts or loss of torque transfer, particularly in reverse or first gear.
- External oil leaks at the bell housing interface: Cracks in the main casing or degraded gaskets allow hydraulic fluid to escape, leading to low pressure and eventual transmission failure.
- Unusual grinding or whining noises during operation: Bearing fatigue or gear tooth pitting within the assembly generates metallic sounds that intensify with speed changes.
- Delayed forward/reverse shuttle response: A failing torque converter or worn spool valves in the valve body create a lag of 2-3 seconds before the machine moves.
Technical Specifications
| Parameter | Value |
|---|---|
| OEM Part Number | 4657.026.307 |
| Assembly Type | 6-Speed Powershift (WG 190) |
| Dry Weight (approx.) | 185 kg (408 lbs) |
| Overall Length | 720 mm |
| Overall Width | 480 mm |
| Overall Height | 510 mm |
| Housing Material | High-Grade Cast Iron (GGG-40) |
| Input Torque Rating | 1,900 Nm (1,401 lb-ft) |
| Fluid Capacity | 22 Liters (5.8 Gallons) |
| OEM Reference | ZF 6 WG 190 |
Compatibility
This complete unit is engineered for the ZF WG 190 series powershift transmissions. It is directly compatible with the WG 180 and WG 200 series when used with the correct adapter plates and input shafts. The assembly also fits select ZF WG 150 and WG 210 variants, though hydraulic line routing may require minor adjustments. For proper installation, the unit must be secured using a HOUS.FRONT SECT and a HOUSING REAR PART to ensure correct alignment of the output shaft. Additionally, the HOUSING REAR SECTION provides critical support for the PTO drive gear.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4657101085 | TRANSMISSION HOUSING | Encloses and protects internal gear sets and shafts |
| 4657201161 | HOUS.FRONT SECT | Front section housing for input shaft and torque converter |
| 4657201162 | HOUSING REAR PART | Rear housing section supporting output flange |
| 4657298107 | HOUSING REAR SECTION | Extended rear section for PTO and brake mounting |
| 0631306816 | CYLINDRICAL PIN | Alignment pin for housing-to-housing dowel fit |
| 0636100801 | CAP SCREW | M12 bolt for securing housing flanges |
| 4656301148 | FIXING PLATE | Locks clutch piston assembly in place |
| 4657301032 | SCREEN SHEET | Fine mesh filter for hydraulic oil return line |
| 4657301033 | SCREEN SHEET | Coarse mesh pre-filter for suction line |
| 0636100803 | CAP SCREW | M14 bolt for heavy-duty housing attachment |
