Overview
The ZF 4644.003.077 WENDEGETRIEBE Powershift Transmission Assembly is a complete, pre-assembled reversing gear unit engineered for heavy-duty industrial drivelines. This assembly integrates the forward and reverse clutch packs within the main transmission housing, enabling seamless direction changes under load without operator clutch engagement. The SKU 4644.003.077 is a direct replacement for the original Wendegtriebe module found in ZF WG 180 and WG 200 series transmissions. It sits between the torque converter and the output shaft housing, acting as the primary directional control unit. For proper installation, this assembly mounts directly onto the TRANSMISSION HOUSING (4644101142), which provides the structural foundation for the entire gear train.
Symptoms of Failure
- Delayed or harsh directional shifts: When the Wendegtriebe clutch packs wear, operators experience a noticeable lag or abrupt engagement when switching from forward to reverse, often accompanied by a metallic clunk.
- Internal oil leaks at the housing interface: Worn seals between the assembly and the HOUSING (4644301301) cause transmission fluid to weep from the joint, leaving puddles under the vehicle after shutdown.
- Loss of power in one direction: A failing unit may provide full torque in forward but slip or fail to engage in reverse, or vice versa, due to degraded clutch friction discs.
- Unusual whining or grinding noise during direction change: Bearing wear inside the assembly produces a high-pitched whine that intensifies as the transmission temperature rises.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 4644.003.077 |
| Assembly Type | WENDEGETRIEBE Powershift (Complete Unit) |
| Overall Length | 385 mm (15.2 in) |
| Overall Width | 310 mm (12.2 in) |
| Overall Height | 275 mm (10.8 in) |
| Dry Weight | 42.5 kg (93.7 lbs) |
| Housing Material | Cast Iron (GGG-40) |
| Clutch Disc Material | Sintered Bronze on Steel |
| OEM Reference | ZF 4644.003.077 |
| Max Input Torque | 1,200 Nm (885 lb-ft) |
| Operating Pressure | 14–18 bar (203–261 psi) |
Compatibility
This complete unit is specifically engineered for the ZF WG 180 series and WG 200 series powershift transmissions. It is a direct fit for models including WG180, WG181, WG182, WG200, WG201, and WG202. The assembly is also compatible with certain variants of the WG 120 series when used with the appropriate ADAPTER (4475280078). Always verify the TYPE PLATE (0730365067) on your existing transmission to confirm model designation before ordering. The unit is secured using the GROOVED STUD (0631311009), which must be torqued to factory specifications during installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101142 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4644301301 | HOUSING | Intermediate housing for clutch pack support |
| 0730365067 | TYPE PLATE | Identification plate with model and serial number |
| 0631311009 | GROOVED STUD | Fastener for securing assembly to housing |
| 4644303060 | COVER PLATE | Seals the top access port of the housing |
| 4644303061 | COVER PLATE | Alternate cover plate for different housing variants |
| 4475280078 | ADAPTER | Interface plate for non-standard transmission mounts |
| 4644106306 | SHIFT SYSTEM | Hydraulic valve body for clutch engagement |
| 4644306499 | COVER PLATE | Lower access cover for oil pan area |
| 4644159351 | SHIFT SYSTEM | Secondary shift control module for dual-clutch setups |
