Overview
The ZF 4651.004.026 4 WG 100(500) Powershift Transmission Assembly is a complete, factory-matched unit engineered for heavy-duty off-highway applications. This assembly integrates the core gear train, clutch packs, and hydraulic control system into a single, ready-to-install package. Designed for the WG 100 Series, the SKU 4651.004.026 serves as the central power transfer module, converting engine torque into precise, multi-speed output for wheel loaders, graders, and industrial vehicles. It is commonly paired with the 4651101007: TRANSMISSION HOUSING to form the primary structural enclosure, and relies on the 0634303928: O-RING for sealing critical hydraulic passages against pressure loss.
Symptoms of Failure
- Delayed or harsh shifting under load: When the internal clutch packs or valve body wear, operators experience hesitation or jarring engagement, especially during directional changes. This is a common search query for “ZF powershift transmission slipping under load.”
- External oil leaks near the bell housing or PTO port: Degraded seals, including the 0634303928: O-RING, allow transmission fluid to escape, leading to low pressure and overheating. Search terms like “ZF transmission oil leak at housing” often point to this issue.
- Loss of power in higher gears: A failing torque converter or worn clutch discs within the 4 WG 100(500) assembly cause the machine to struggle reaching top speed, particularly on inclines. This symptom is frequently searched as “transmission won’t shift into high gear ZF.”
- Unusual whining or grinding noises: Bearing failure or contamination in the gear train produces metallic sounds that intensify with RPM. This often correlates with a damaged 4651301029: HOUSING or misaligned internal components.
Technical Specifications
| Parameter | Value |
|---|---|
| Assembly Weight | ~185 kg (408 lbs) |
| Overall Length | 720 mm |
| Overall Width | 480 mm |
| Overall Height | 510 mm |
| Housing Material | Cast Iron (GGG-40) |
| OEM Reference | ZF 4651.004.026 / 4 WG 100(500) |
| Max Input Torque | 500 Nm |
| Number of Speeds | 4 Forward / 4 Reverse |
| Seal Type | Viton O-Ring (0634303928 compatible) |
Compatibility
This complete unit is specifically designed for the ZF WG 100 Series, including the 4 WG 100 and 4 WG 100(500) variants. It is also mechanically compatible with the WG 120 and WG 150 series when used with the appropriate 4651301024: HOUSING adapter. For WG 180 or WG 200 models, internal clutch pack configurations differ, but the main mounting bolt pattern matches when using the 4651101007: TRANSMISSION HOUSING. Always verify bell housing alignment and PTO interface before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4651101007 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4651301029 | HOUSING | Rear cover for clutch pack access |
| 0634303928 | O-RING | Hydraulic seal between housing sections |
| 4651301024 | HOUSING | Intermediate adapter housing |
| 4651203002 | SCREEN SHEET | Oil filter mesh for hydraulic circuit |
| 4651303005 | SCREEN SHEET | Secondary oil strainer |
| 0636101032 | CAP SCREW | Fastener for housing assembly |
| 0630361028 | SEALING CAP | Port plug for test points |
| 4475280060 | SCREW PLUG | Drain/fill plug |
| 0634303312 | O-RING | Seal for screw plug |
