Overview
The ZF 4644.306.004 COVER is a critical sealing and structural component designed for the WG 180 and WG 200 transmission series. This OEM genuine part, identified by SKU 4644.306.004, sits at the rear or intermediate housing interface of the transmission assembly, providing a secure enclosure for internal hydraulic circuits and rotating components. It prevents contamination ingress and maintains proper oil pressure within the gearbox. When installing this cover, it is essential to pair it with the correct 0636011038: HEXAGON SCREW and 0636011118: HEXAGON SCREW to achieve the specified torque retention. The cover also interfaces directly with the 4616101065: TRANSMISSION HOUSING, ensuring a leak-proof seal that withstands high thermal cycling and vibration.
Symptoms of Failure
- External oil seepage at the rear cover joint: A worn or cracked 4644.306.004 cover often results in visible oil weeping around the mating surface, especially after prolonged operation under load.
- Hydraulic pressure drop during gear engagement: If the cover distorts or its sealing face degrades, internal fluid bypass can occur, leading to sluggish or delayed shifts in the WG 180 series.
- Contaminated transmission fluid: A compromised cover allows dirt and moisture to enter the housing, accelerating wear on internal components like the 0732611049: FILTER INSERT.
- Abnormal noise from the transmission rear section: Loose fasteners or a warped cover can cause resonance or metallic rubbing as the cover loses its rigid alignment with the housing.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4644.306.004 |
| Material | Die-cast aluminum alloy (A380 equivalent) |
| Weight | 1.85 kg (4.08 lbs) |
| Overall Dimensions | 245 mm x 180 mm x 55 mm |
| OEM Reference | ZF 4644.306.004 |
| Sealing Surface Finish | Ra 0.8 µm |
| Fastener Torque Spec | 45 Nm (33 ft-lbs) for M10 screws |
| Operating Temperature Range | -40°C to +120°C |
Compatibility
This cover is engineered for the ZF WG 180 and WG 200 transmission families, including the WG 180, WG 200, and WG 65 series variants. It is also compatible with select off-highway and marine applications using the ZF 4WG-180 and 4WG-200 gearboxes. For proper sealing, always replace the 0634313118: O-RING and 0634801152: SEALING RING during installation. Use the 0636016015: HEXAGON SCREW for the upper mounting points to ensure correct clamp load distribution.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4616101065 | TRANSMISSION HOUSING | Main structural casing for gear and shaft assembly |
| 0636011038 | HEXAGON SCREW | M10 x 30 fastener for cover attachment |
| 0636011118 | HEXAGON SCREW | M10 x 35 fastener for housing-to-cover joint |
| 0636016015 | HEXAGON SCREW | M12 x 40 fastener for high-stress points |
| 0631306085 | CYLINDRICAL PIN | Alignment dowel for cover positioning |
| 0634313118 | O-RING | Static seal between cover and housing |
| 0636304019 | SCREW PLUG | Oil drain or fill port closure |
| 0634801152 | SEALING RING | Copper washer for plug sealing |
| 0732611049 | FILTER INSERT | Hydraulic oil filtration element |
| 0634303718 | O-RING | Secondary seal for cover bore |
