Overview
The ZF 4651.004.033 4 WG 100(500) Powershift Transmission Assembly is a complete, factory-matched unit designed for heavy-duty off-highway applications. This assembly integrates the torque converter, clutch packs, and planetary gear sets into a single, ready-to-install package. As the core of the WG 100 series drivetrain, it manages power distribution from the engine to the final drives, ensuring smooth directional shifts and load-holding capability under extreme torque. The SKU 4651.004.033 is a direct replacement for original equipment, eliminating the need for piecemeal repairs. When rebuilding, always inspect the TRANSMISSION HOUSING (4651101007) for cracks, as it supports the entire assembly. Additionally, verify the condition of the HOUSING (4651301029) which seals the clutch drum area against contamination.
Symptoms of Failure
- Delayed engagement or gear slipping under load: When the 4 WG 100(500) assembly loses internal pressure, you may experience a hesitation of 2-3 seconds before the machine moves, or the transmission slips out of gear on inclines. This often points to worn clutch discs or a failing torque converter stator.
- External oil leaks near the bell housing or PTO cover: A common failure mode is seepage from the main gasket or seal interfaces. If you notice puddles of ATF under the chassis, check the O-RING (0634303928) which seals the oil pump cover, as a degraded O-ring is a frequent culprit.
- Grinding or whining noise during directional shifts: A high-pitched whine when shifting from forward to reverse indicates worn planetary bearings or a damaged sun gear. This noise often precedes a complete loss of drive.
- Overheating and burnt fluid odor: If the transmission runs hot (above 230°F) and the fluid smells burnt, the internal clutches are slipping excessively. This is often accompanied by a failure of the HOUSING (4651301024) which contains the lube oil circuit.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4651.004.033 |
| Assembly Type | 4 WG 100(500) Powershift |
| Dry Weight (approx.) | 185 kg (408 lbs) |
| Overall Length | 720 mm |
| Overall Width | 480 mm |
| Overall Height | 560 mm |
| Housing Material | Cast Iron (GGG-40) |
| OEM Reference | ZF 4 WG 100(500) |
| Max Input Torque | 500 Nm |
| Fluid Capacity | 12.5 liters (ATF Dexron III) |
Compatibility
This complete unit is specifically engineered for the ZF WG 100 series, which includes the WG 100(500) and WG 100(600) variants. It is also backward-compatible with earlier 4 WG 100 models found in telehandlers, wheel loaders, and agricultural tractors. While the WG 180 and WG 200 series share similar internal architecture, the 4651.004.033 assembly is not directly interchangeable due to differences in bell housing bolt patterns and torque converter stall speeds. Always confirm your transmission model tag before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4651101007 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4651301029 | HOUSING | Clutch drum cover and oil distribution |
| 0634303928 | O-RING | Seals oil pump to housing interface |
| 4651301024 | HOUSING | Lube oil circuit and valve body mount |
| 4651203002 | SCREEN SHEET | Fine mesh filter for hydraulic circuit |
| 4651303005 | SCREEN SHEET | Coarse debris screen for sump pickup |
| 0636101032 | CAP SCREW | Fastener for housing assembly |
| 0630361028 | SEALING CAP | Plugs unused hydraulic ports |
| 4475280060 | SCREW PLUG | Drain or fill port closure |
| 0634303312 | O-RING | Seals screw plug against leakage |
