Overview
The ZF 4616.321.057 SPACER BUSH for WG65 is a precision-engineered component designed to maintain exact axial clearance and alignment within the WG 65 series transmission assembly. This OEM genuine part, identified by SKU 4616.321.057, sits between the transmission housing and the rotating shaft assembly, ensuring that gear clusters remain properly spaced under heavy torque loads. By providing a hardened, wear-resistant interface, this spacer bush prevents metal-on-metal contact that could lead to premature gear degradation. It works in concert with the 4616101059: TRANSMISSION HOUSING to create a stable foundation for the planetary gear sets, and is secured using 0636011038: HEXAGON SCREW fasteners during installation.
Symptoms of Failure
When the 4616.321.057 spacer bush wears beyond tolerance, operators typically encounter these specific failure indicators:
- Oil leaks near the shaft seal area – Worn bushings allow shaft wobble, breaking the seal between the 0634313118: O-RING and the housing.
- Gear slipping under load – Loss of axial preload causes gear clusters to shift, resulting in intermittent power transfer during acceleration.
- Metallic grinding noise from the WG65 housing – Direct contact between the shaft and the TRANSMISSION HOUSING produces a distinct high-pitched whine or grinding sound.
- Increased vibration at the output flange – Uneven bushing wear creates rotational imbalance that transmits through the driveline.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4616.321.057 |
| Outer Diameter | 42.0 mm |
| Inner Diameter | 32.0 mm |
| Length | 28.5 mm |
| Material | Case-hardened steel (16MnCr5) |
| Weight | 0.085 kg |
| OEM Reference | ZF 4616.321.057 |
| Surface Hardness | 58-62 HRC |
Compatibility
This spacer bush is specifically engineered for the ZF WG 65 Series transmissions. Based on its dimensional profile and application, it is also compatible with the following ZF models that share the same planetary carrier architecture: WG180, WG200, WG210, and WG250. Always verify fitment by cross-referencing the part number against your transmission’s serial plate. When replacing this bush, it is recommended to also inspect the 0636011118: HEXAGON SCREW and 0636016015: HEXAGON SCREW for thread wear, as these fasteners secure the bush in place.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4616101059 | TRANSMISSION HOUSING | Main structural casing for gear assembly |
| 0636011038 | HEXAGON SCREW | Secures housing to bell housing |
| 0636011118 | HEXAGON SCREW | Fastens spacer bush retaining plate |
| 0636016015 | HEXAGON SCREW | Mounts oil pump to housing |
| 0631306085 | CYLINDRICAL PIN | Aligns housing halves during assembly |
| 0634313118 | O-RING | Seals oil passage between housing sections |
| 0636304019 | SCREW PLUG | Closes oil drain port in housing |
| 0634801152 | SEALING RING | Prevents leakage at plug interface |
| 0732611049 | FILTER INSERT | Traps debris in hydraulic circuit |
| 0634303718 | O-RING | Seals filter housing cover |
