Overview
The ZF 4651.004.044 4 WG 100(500) Powershift Transmission Assembly represents a complete, factory-matched unit designed for heavy-duty off-highway applications. This assembly integrates the full gear train, clutch packs, and hydraulic control system into a single ready-to-install package. As a direct replacement for the WG 100 series, it ensures seamless integration with existing drivelines. The SKU 4651.004.044 is critical for identifying the correct assembly variant, which includes the reinforced output shaft and upgraded valve body for higher torque capacity. This unit sits at the heart of the powertrain, converting engine torque into controlled, shiftable power for loaders, graders, and material handlers.
Symptoms of Failure
- Delayed or harsh engagement: When the transmission hesitates before moving or slams into gear, it often indicates worn clutch discs or degraded seals within the assembly. This is a common search query for “ZF WG100 hard shifting fix.”
- Oil leaks at housing joints: External fluid seepage around the bell housing or main case points to failing gaskets or cracks. Searching for “ZF 4651.004.044 oil leak repair” typically leads to this issue.
- Intermittent gear slipping under load: A sudden loss of power during acceleration, especially on inclines, suggests internal pressure loss or worn friction plates. This symptom is frequently queried as “WG100 transmission slipping under load.”
- Unusual whining or grinding noises: Metallic sounds from the transmission sump indicate bearing failure or gear tooth damage, often requiring immediate assembly replacement.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4651.004.044 |
| Assembly Type | Complete Powershift Unit (4 WG 100/500) |
| Dry Weight (approx.) | 185 kg (408 lbs) |
| Overall Length | 620 mm |
| Housing Material | Cast Iron (GGG-40) |
| Max Input Torque | 500 Nm |
| OEM Reference | ZF 4651.004.044 |
| Fluid Capacity | 12.5 liters (ATF Dexron III) |
Compatibility
This assembly is engineered for the ZF WG 100 series transmissions, specifically the 4 WG 100(500) variant. It is directly compatible with models including the WG 100, WG 180, and WG 200 when used in applications such as telescopic handlers, wheel loaders, and backhoe loaders. The unit also fits select WG 120 and WG 150 configurations with minor adapter plate modifications. Always verify the bell housing pattern and output flange dimensions against your original unit before installation.
During installation, ensure the TRANSMISSION HOUSING (4651101007) is free of cracks and the mating surfaces are clean. The HOUSING (4651301029) must be torqued to specification to prevent misalignment. A fresh O-RING (0634303928) is required for the main pressure line seal, and the HOUSING (4651301024) should be inspected for wear at the bearing journals.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4651101007 | TRANSMISSION HOUSING | Main structural case for gear and clutch assembly |
| 4651301029 | HOUSING | Rear cover housing for output shaft support |
| 0634303928 | O-RING | Hydraulic seal for main pressure circuit |
| 4651301024 | HOUSING | Intermediate housing for clutch pack retention |
| 4651203002 | SCREEN SHEET | Fine mesh filter for hydraulic oil return line |
| 4651303005 | SCREEN SHEET | Coarse strainer for sump pickup protection |
| 0636101032 | CAP SCREW | M10x30 bolt for housing flange fastening |
| 0630361028 | SEALING CAP | Plugs unused hydraulic test ports |
| 4475280060 | SCREW PLUG | Drain plug with magnet for debris collection |
| 0634303312 | O-RING | Seal for screw plug and cap screw interfaces |
