Overview
The ZF 4651.004.003 4 WG 100(500) Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway applications. This assembly integrates the clutch pack, planetary gearsets, and hydraulic control system into a single, ready-to-install package. As the core power transfer module in the WG 100 series, it replaces worn or failed assemblies to restore original shift quality and torque capacity. The SKU 4651.004.003 is a direct OEM-spec replacement, ensuring precise fitment and performance in ZF drivelines.
Symptoms of Failure
- Delayed or harsh engagement: When the assembly wears, hydraulic pressure drops, causing a noticeable lag when shifting from neutral to forward or reverse. This often manifests as a “clunk” or jerky start.
- Intermittent gear slipping under load: Worn clutch discs or piston seals within the 4651.004.003 can cause the transmission to lose torque during uphill climbs or heavy pulling, with the engine revving but vehicle speed not increasing.
- External oil leaks near the bell housing: Degraded O-rings or housing cracks allow transmission fluid to seep out, leaving puddles under the vehicle. This is often accompanied by a burnt smell from overheated fluid.
- Erratic shift patterns or no movement: Complete internal failure of the assembly may result in the transmission staying in one gear or refusing to engage any gear, requiring immediate replacement of the unit.
Technical Specifications
| Specification | Value |
|---|---|
| OEM Part Number | 4651.004.003 |
| Assembly Type | 4 WG 100(500) Powershift |
| Dry Weight (approx.) | 185 kg (408 lbs) |
| Overall Length | 620 mm |
| Overall Width | 480 mm |
| Overall Height | 510 mm |
| Housing Material | High-strength cast iron |
| Max Input Torque | 500 Nm |
| Fluid Capacity (assembly only) | 4.5 liters |
Compatibility
This complete unit is engineered for the ZF WG 100 series, specifically the 4 WG 100(500) variant. It is also compatible with the WG 180 and WG 200 series when used with the correct TRANSMISSION HOUSING (4651101004) and HOUSING (4651301014). For proper sealing during installation, always replace the O-RING (0634303928) and verify the condition of the TRANSMISSION HOUSING (4651301008) to prevent leaks. This assembly is commonly found in ZF 4WG-100, 4WG-180, and 4WG-200 powershift transmissions used in loaders, graders, and industrial tractors.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4651101004 | TRANSMISSION HOUSING | Main structural casing for the gearset |
| 4651301014 | HOUSING | Rear cover and bearing support |
| 0634303928 | O-RING | Seals the housing-to-assembly interface |
| 4651301008 | TRANSMISSION HOUSING | Front housing for clutch pack retention |
| 4651203002 | SCREEN SHEET | Filters debris from hydraulic fluid |
| 4651303005 | SCREEN SHEET | Secondary filtration for oil return line |
| 0636101032 | CAP SCREW | Fastens housing sections together |
| 0630361028 | SEALING CAP | Closes unused hydraulic ports |
| 0636304032 | SCREW PLUG | Drain or fill port closure |
| 0634303312 | O-RING | Seals the screw plug and cap screw |
