Overview
The ZF 4651.004.027 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 gear sets, and hydraulic control components into a single, ready-to-install package. As the core power transfer module within the WG 100 Series, it directly replaces worn or failed assemblies to restore full torque capacity and shift precision. The SKU 4651.004.027 is a direct OEM reference, ensuring a precise fit without modification. This unit sits between the torque converter and the output shaft, managing gear ratio changes under load. For a full rebuild, pair this assembly with a new TRANSMISSION HOUSING to guarantee structural integrity and alignment.
Symptoms of Failure
- Delayed or harsh engagement when shifting from neutral to drive: Worn internal seals within the 4651.004.027 cause pressure loss, leading to a noticeable lag or a jarring clunk during engagement.
- Intermittent gear slipping under load: As clutch discs wear, the transmission may momentarily lose power delivery, especially when climbing grades or carrying heavy payloads.
- Contaminated transmission fluid with metallic debris: Internal bearing or gear wear generates fine metal particles that appear in the oil, often accompanied by a burnt smell from overheated friction material.
- Constant low hydraulic pressure or erratic shift patterns: A failing assembly cannot maintain steady pressure, causing the transmission to hunt between gears or fail to hold a selected gear.
Technical Specifications
| Parameter | Value |
|---|---|
| OEM Part Number | 4651.004.027 |
| Assembly Type | 4 WG 100(500) Powershift |
| Dry Weight (approx.) | 185 kg (408 lbs) |
| Overall Length | 620 mm |
| Housing Material | High-strength cast iron |
| Seal Material | Nitrile rubber (NBR) |
| Max Input Torque | 500 Nm (369 lb-ft) |
| Number of Speeds | 4 forward / 4 reverse |
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 120 and WG 150 series transmissions found in telehandlers, wheel loaders, and agricultural tractors. For models like the WG 180 or WG 200, verify bell housing and output flange dimensions, as the 4651.004.027 uses a specific bolt pattern. When installing, always replace the HOUSING and O-RING to prevent fluid leaks. Additionally, inspect the HOUSING for cracks or wear before reassembly.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4651101007 | TRANSMISSION HOUSING | Main structural casing for gear and shaft support |
| 4651301029 | HOUSING | Intermediate housing for clutch pack retention |
| 0634303928 | O-RING | Static seal between housing sections |
| 4651301024 | HOUSING | Rear housing for output shaft support |
| 4651203002 | SCREEN SHEET | Fine mesh filter for hydraulic fluid |
| 4651303005 | SCREEN SHEET | Secondary filter for valve body protection |
| 0636101032 | CAP SCREW | High-tensile fastener for housing assembly |
| 0630361028 | SEALING CAP | Port plug for pressure test points |
| 4475280060 | SCREW PLUG | Drain plug with magnetic insert |
| 0634303312 | O-RING | Seal for screw plug and cap screw |
