Overview
The ZF 4068.306.029 COMPRESSION SPRING is a critical load-bearing component engineered for the WG65, WG150, WG180, and WG200 series transmissions. This OEM genuine part provides precise axial force within the valve body or clutch pack assembly, ensuring consistent hydraulic pressure modulation and smooth gear engagement. The SKU 4068.306.029 is manufactured to ZF’s exacting tolerances to maintain spring rate stability under high-cycle thermal and mechanical stress. When installed alongside the 4616101059 TRANSMISSION HOUSING, this spring ensures proper alignment of internal shift components, preventing premature wear in the actuation circuit.
Symptoms of Failure
- Delayed or harsh shifting – A worn compression spring loses its calibrated force, causing sluggish engagement or abrupt gear changes, particularly in WG65 and WG200 series units.
- Intermittent pressure loss – When the spring fatigues, it fails to maintain consistent valve seating, leading to transient hydraulic drops that trigger fault codes for clutch slip.
- Audible clicking or rattling – A broken or collapsed spring allows loose metallic contact within the bore, producing distinct noise during transmission operation under load.
- Erratic shift pattern – The spring’s reduced preload causes the valve spool to float, resulting in unpredictable shift timing and increased wear on the 0636011038 HEXAGON SCREW and adjacent fasteners.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4068.306.029 |
| Material | Chrome-silicon alloy spring steel (DIN EN 10270-2) |
| Wire Diameter | 3.2 mm (estimated) |
| Outer Diameter | 22.5 mm (estimated) |
| Free Length | 48.0 mm (estimated) |
| Spring Rate | 45 N/mm (estimated) |
| Weight | 0.035 kg |
| OEM Reference | ZF 4068.306.029 |
| Surface Treatment | Phosphate coated with oil film |
Compatibility
This compression spring is a direct-fit OEM replacement for ZF WG65, WG150, WG180, and WG200 series transmissions produced after 2005. It is specifically designed for the valve body assembly that controls clutch modulation and shift timing. The spring interfaces with the 0636011118 HEXAGON SCREW and 0636016015 HEXAGON SCREW used to secure the valve body cover. For complete assembly, verify that the 0631306085 CYLINDRICAL PIN and 0634313118 O-RING are also inspected during service. This spring is not interchangeable with earlier WG series variants without cross-referencing the transmission serial number.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4616101059 | TRANSMISSION HOUSING | Main structural casing for gear and valve assemblies |
| 0636011038 | HEXAGON SCREW | Fastener for valve body retention |
| 0636011118 | HEXAGON SCREW | Mounting bolt for clutch pack cover |
| 0636016015 | HEXAGON SCREW | Secures oil pump housing |
| 0631306085 | CYLINDRICAL PIN | Alignment dowel for valve body positioning |
| 0634313118 | O-RING | Seals valve body oil passages |
| 0636304019 | SCREW PLUG | Closes test ports in housing |
| 0634801152 | SEALING RING | Prevents external oil leakage |
| 0732611049 | FILTER INSERT | Traps debris in lubrication circuit |
| 0634303718 | O-RING | Seals filter housing interface |
