Overview
The ZF 4644.308.186 BUSH for WG201 is a precision-engineered, OEM genuine replacement component designed to serve as a critical wear surface within the planetary gearset of ZF’s WG series transmissions. This bushing acts as a sacrificial liner, reducing friction between rotating shafts and stationary housings, thereby maintaining precise gear alignment and hydraulic pressure integrity. The SKU 4644.308.186 is specifically manufactured to factory tolerances for the WG201 model, ensuring a direct fit without modification. When installed alongside a robust TRANSMISSION HOUSING (4644101160) or a TRANSMISSION HOUSING (4644301323), this bushing forms the foundational support for the entire rotating assembly.
Symptoms of Failure
- Low hydraulic pressure and gear slipping: A worn 4644.308.186 bushing allows excessive shaft play, causing oil to bypass seals and reducing clutch pack engagement pressure. This often manifests as a delayed shift or a “flare” between gears.
- Metallic debris in the transmission pan: As the bushing material degrades, bronze or steel particles contaminate the fluid. This is a primary indicator of bushing fatigue, often found during routine oil changes.
- Audible whining or knocking from the transmission housing: Excessive clearance between the shaft and the worn bushing generates a distinct low-frequency hum or a rhythmic knock under load, particularly in the WG201 series.
- Oil leaks near the bell housing or output flange: A compromised bushing can distort the shaft seal surface, leading to chronic fluid seepage that worsens with transmission temperature.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (SKU) | 4644.308.186 |
| OEM Reference | ZF 4644.308.186 |
| Material | Steel-backed sintered bronze (lead-free) |
| Inner Diameter (Nominal) | 38.10 mm (1.500 in) |
| Outer Diameter (Nominal) | 44.45 mm (1.750 in) |
| Length | 25.40 mm (1.000 in) |
| Weight | 0.08 kg (0.18 lbs) |
| Hardness | HRB 60-70 (core) |
| Operating Temperature Range | -40°C to +150°C |
Compatibility
This bushing is engineered for the ZF WG201 transmission series. Based on its dimensional profile and material composition, the 4644.308.186 is also compatible with the WG180, WG200, and WG210 models where similar planetary carrier bushings are utilized. It is a direct replacement for the original bushing found in the output shaft support bore. For complete assembly integrity, always pair this bushing with a new THREADED BUSH (4644301189) and a SCREW PLUG (4475280043) to secure the lubrication gallery.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101160 | TRANSMISSION HOUSING | Main structural casing for gear and shaft alignment |
| 4644301323 | TRANSMISSION HOUSING | Alternate housing variant for WG200 series |
| 4644301189 | THREADED BUSH | Provides threaded anchor for sensor or plug installation |
| 4475280043 | SCREW PLUG | Seals hydraulic passages in the valve body |
| 0634306198 | O-RING | Prevents fluid bypass between mating surfaces |
| 0730365067 | TYPE PLATE | Identification plate for transmission model |
| 4644301161 | COVER PLATE | Encloses the clutch pack access port |
| 0636100621 | HEXAGON SCREW | Fastener for housing and cover plate attachment |
| 0631610020 | SET SCREW | Locks adjustment mechanisms in the shift linkage |
| 0501218540 | BREATHER | Vents internal pressure to prevent seal damage |
