Overview
The ZF 4644.084.005 4 WG 181 Powershift Transmission Assembly | Complete Unit is a fully assembled drop-in solution designed for heavy-duty off-highway machinery. As a core component of the WG 181 series, this complete unit integrates the main gear cluster, clutch packs, and hydraulic control valving into a single, ready-to-install package. The SKU 4644.084.005 identifies a factory-spec assembly that replaces the entire transmission core, eliminating the need for piecemeal rebuilding. It sits directly between the torque converter and the output flange, serving as the primary power transfer module. For proper sealing and alignment, this unit mates with the TRANSMISSION HOUSING (4644101047) and the HOUSING (4644301380).
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 during operation, often accompanied by a burning smell.
- External oil leaks at the main case seam: Degraded gaskets or cracks in the housing lead to fluid seepage around the mid-plate, requiring replacement of the THREADED BUSH (4644301189) and sealing rings.
- Unusual grinding or whining noise from the gear train: Bearing fatigue or gear tooth spalling within the assembly generates metallic noise, especially in forward gears.
- Loss of hydraulic pressure and overheating: Internal leakage past worn valve bodies reduces clutch apply pressure, causing the transmission to run hot and eventually fail to move.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number / SKU | 4644.084.005 |
| Assembly Type | Complete Powershift Unit (4 WG 181) |
| OEM Reference | ZF 4 WG 181 |
| Estimated Weight | 185 kg (408 lbs) |
| Overall Dimensions (L x W x H) | 610 mm x 480 mm x 420 mm |
| Primary Material | Cast Iron Housing with Hardened Steel Gears |
| Max Input Torque | 1,200 Nm (885 lb-ft) |
| Number of Speeds | 4 Forward / 4 Reverse |
| Fluid Capacity | 18 liters (4.75 gallons) |
Compatibility
This complete unit is engineered for the ZF WG 181 series and is also backward-compatible with the WG 180 and WG 200 series transmissions found in telehandlers, wheel loaders, and industrial tractors. It directly replaces earlier 4-speed powershift variants. For identification, always verify the TYPE PLATE (0730365067) on your existing unit to confirm model and serial number range.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101047 | TRANSMISSION HOUSING | Main structural casing for gear support |
| 4644301380 | HOUSING | Rear cover housing for output shaft |
| 4644301189 | THREADED BUSH | Oil passage alignment and sealing |
| 0730365067 | TYPE PLATE | Identification and rating label |
| 0631311009 | GROOVED STUD | Alignment dowel for housing mating |
| 4644301161 | COVER PLATE | Access cover for valve body |
| 0636100621 | HEXAGON SCREW | Fastener for housing assembly |
| 0631610020 | SET SCREW | Adjustable stop for shift linkage |
| 0634801098 | SEALING RING | O-ring for hydraulic circuit sealing |
| 4644301117 | FIXING PLATE | Retainer for clutch piston |
