Overview
The ZF 0732.040.238 COMPRESSION SPRING is a precision-engineered OEM genuine component designed for the valve body and shift control assemblies within ZF WG100, WG130, and WG131 transmissions. This spring provides the necessary preload and return force for hydraulic spools and pistons, ensuring consistent oil pressure regulation and smooth gear engagement. The SKU 0732.040.238 is critical for maintaining the calibrated spring rate required by the transmission’s control logic. When installed alongside the 4143101022 HOUSING and the 4143301044 HOUSING, this compression spring ensures the entire valve body assembly operates without binding or pressure loss.
Symptoms of Failure
When the ZF 0732.040.238 compression spring fatigues or breaks, operators will notice distinct performance issues. Delayed or harsh shifting occurs because the spring can no longer return the valve spool to its neutral position quickly. Intermittent gear slipping under load is another common symptom, as the weakened spring allows the valve to drift, reducing clutch pack pressure. Erratic transmission behavior during cold starts often points to a spring that has lost its temper, failing to provide consistent force in low-viscosity oil. Finally, unusual hydraulic noise or buzzing from the valve body may indicate the spring is vibrating against the 0631329135 SPRING PIN due to insufficient preload.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number | 0732.040.238 |
| Type | Helical Compression Spring |
| Material | Chrome Silicon Alloy Steel (EN 10270-2) |
| Wire Diameter | 2.5 mm (est.) |
| Outer Diameter | 18.0 mm (est.) |
| Free Length | 42.0 mm (est.) |
| Spring Rate | 12.5 N/mm (est.) |
| Surface Treatment | Phosphate & Oil |
| Weight | 0.015 kg |
| OEM Reference | ZF 0732.040.238 |
Compatibility
This genuine ZF compression spring is specifically engineered for the following transmission models: WG100, WG130, and WG131. It is a direct replacement for the original spring installed in the main control valve body and the modulating pressure regulator section. While the spring is not used in WG180 or WG200 series transmissions, it is a mandatory component for any rebuild of the WG100/130/131 valve body assembly. Always verify that the 0636302014 SCREW PLUG is properly torqued when replacing this spring to prevent oil bypass.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4143101022 | HOUSING | Main valve body housing |
| 4143301044 | HOUSING | Secondary valve body housing |
| 0631329135 | SPRING PIN | Retains spring in bore |
| 0636302014 | SCREW PLUG | Seals valve body port |
| 0634801057 | SEALING RING | Prevents oil leakage |
| 4143301053 | CONNECTING PART | Links valve body sections |
| 0636100600 | CAP SCREW | Fastens housing halves |
| 0636101024 | CAP SCREW | Secures valve body to case |
| 0730365159 | TYPE PLATE | Identification label |
| 0631311009 | GROOVED STUD | Alignment dowel for housing |
