Overview
The ZF 4644.306.585 FILLER PIECE is a precision-engineered OEM genuine component designed specifically for the WG 100 Series transmission family. This critical spacer element sits within the lower valve body assembly, ensuring correct oil channel alignment and maintaining proper hydraulic pressure distribution throughout the gear train. The part number 4644.306.585 serves as the exact factory-specified filler piece that prevents cross-leakage between circuits, directly supporting the structural integrity of the adjacent 4651101006: TRANSMISSION HOUSING and the 4651301034: HOUSING assembly. Without this filler piece, the transmission cannot maintain the precise clearances required for reliable shifting under heavy industrial loads.
Symptoms of Failure
When the ZF 4644.306.585 filler piece begins to degrade or becomes misaligned, operators typically notice these specific failure indicators:
- Oil leaks at the housing interface – A worn filler piece allows pressurized ATF to escape between the 4651301013: HOUSING and the valve body, leading to visible drips or wet spots on the transmission exterior.
- Erratic or delayed gear engagement – Loss of hydraulic sealing causes inconsistent clutch pack application, resulting in harsh shifts or hesitation when moving from neutral to drive.
- Low line pressure warnings – Internal bypass of fluid past a damaged filler piece triggers diagnostic trouble codes for insufficient main circuit pressure, often accompanied by slipping under load.
- Contaminated transmission fluid – A cracked filler piece can introduce debris into the oil galleries, accelerating wear on the 0634303928: O-RING seals and other precision components.
Technical Specifications
| Specification | Detail |
|---|---|
| OEM Part Number | 4644.306.585 |
| Material | High-grade aluminum alloy with anodized surface |
| Length | 48.5 mm |
| Width | 22.0 mm |
| Height | 6.2 mm |
| Weight | 18 grams |
| OEM Reference | ZF 4644.306.585 (Genuine) |
| Operating Temperature Range | -40°C to +120°C |
Compatibility
This filler piece is engineered for the WG 100 Series of ZF industrial transmissions, including models WG100, WG120, WG150, WG180, and WG200. It is also compatible with select WG 80 variants that share the same valve body architecture. The part directly interfaces with the 4651101006: TRANSMISSION HOUSING and the 4651301034: HOUSING, making it essential for any rebuild or overhaul of these heavy-duty transmissions used in construction, mining, and agricultural equipment.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4651101006 | TRANSMISSION HOUSING | Main structural casing for gear and valve body assembly |
| 4651301034 | HOUSING | Secondary housing supporting clutch pack and oil circuits |
| 0634303928 | O-RING | Seals fluid passages between housing and valve body |
| 4651301013 | HOUSING | Lower housing component for oil distribution |
| 4651301015 | SCREEN SHEET | Fine mesh filter protecting hydraulic circuits from debris |
| 4651301035 | SCREEN SHEET | Secondary filter screen for high-pressure oil galleries |
| 0630361028 | SEALING CAP | Closes unused ports to prevent fluid loss |
| 4475280060 | SCREW PLUG | Threaded plug for drain or test points |
| 0634303312 | O-RING | Elastomeric seal for screw plug interfaces |
| 0630361063 | SEALING CAP | Dust and moisture cap for external sensor ports |
