Overview
The ZF 4644.036.061 6 WG 201 Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway machinery. This assembly serves as the core power transfer module within the WG 201 series, integrating the torque converter, planetary gear sets, and hydraulic clutch packs into a single, pre-assembled housing. As a direct replacement for the SKU 4644.036.061, this unit eliminates the need for piecemeal rebuilding, ensuring precise gear engagement under high-load conditions. It sits centrally in the drivetrain, converting engine torque into controlled, multi-speed output for wheel loaders, graders, and industrial tractors.
Symptoms of Failure
- Delayed or harsh engagement when shifting from neutral to forward or reverse: This indicates internal clutch pack wear or hydraulic pressure loss within the assembly, often accompanied by a loud “clunk” during gear changes.
- Persistent transmission fluid leaks near the bell housing or output flange: Worn seals or cracks in the TRANSMISSION HOUSING can cause fluid loss, leading to overheating and erratic shifting.
- Intermittent gear slipping under load, especially on inclines: A failing powershift unit may lose torque lock-up, causing the engine to rev without proportional vehicle movement.
- Unusual whining or grinding noises from the transmission center section: This points to bearing degradation or gear tooth damage inside the assembly, requiring immediate replacement to prevent catastrophic failure.
Technical Specifications
| Specification | Detail |
|---|---|
| OEM Part Number | 4644.036.061 |
| Series | WG 201 (6-Speed Powershift) |
| Overall Length | Approx. 680 mm |
| Dry Weight | Approx. 185 kg (408 lbs) |
| Housing Material | High-tensile cast iron |
| Input Torque Capacity | Up to 1,200 Nm |
| Hydraulic Pressure Range | 14–18 bar (203–261 psi) |
| Associated Sealing Kit | 0634306198: O-RING, 0634801098: SEALING RING |
| Identification | 0730365067: TYPE PLATE |
| Mounting Hardware | 0631311009: GROOVED STUD, 0636100621: HEXAGON SCREW |
Compatibility
This complete unit is engineered for the ZF WG 201 series, but its core architecture shares components with the WG 180 and WG 200 families. It is a direct fit for models such as the WG 201-6, WG 201-8, and select WG 200 variants used in construction equipment from 2005 onward. The assembly requires a compatible TRANSMISSION HOUSING (SKU 4644301390) for proper alignment. Always verify the bell housing pattern and output flange configuration against your existing unit before installation.
During installation, technicians must also inspect the THREADED BUSH (SKU 4644301189) for wear, as this component secures the hydraulic feed lines. Additionally, the SCREW PLUG (SKU 0636302005) should be replaced to prevent fluid bypass. For units requiring a cover plate upgrade, the 4644301161: COVER PLATE is recommended to seal the valve body access port.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101172 | TRANSMISSION HOUSING | Main structural casing for gear sets |
| 4644301390 | TRANSMISSION HOUSING | Alternate housing variant for WG 200 series |
| 4644301189 | THREADED BUSH | Hydraulic line anchor point |
| 0636302005 | SCREW PLUG | Seals oil drain or test ports |
| 0634306198 | O-RING | Hydraulic seal for clutch pistons |
| 0634801098 | SEALING RING | Static seal for housing joints |
| 0730365067 | TYPE PLATE | Identification tag with serial number |
| 0631311009 | GROOVED STUD | Alignment dowel for housing mating |
| 4644301161 | COVER PLATE | Access cover for valve body |
| 0636100621 | HEXAGON SCREW | Fastener for housing assembly |
