Overview
The ZF 5838.300.315 CUP SPRING is a precision-engineered component designed for the WG100, WG130, and WG131 transmission series. This OEM genuine part plays a critical role in maintaining consistent preload within the differential assembly, ensuring that the DIFFERENTIAL gears remain properly seated under varying torque loads. Positioned inside the axle housing, the cup spring absorbs axial play and compensates for thermal expansion, directly influencing shift quality and drivetrain longevity. The SKU 5838.300.315 is manufactured to ZF’s exacting tolerances, making it a direct replacement for worn units in heavy-duty industrial applications.
Symptoms of Failure
When the 5838.300.315 cup spring loses its tensile strength, several distinct failure modes emerge. Oil leaks around the axle seals often occur first, as reduced spring pressure allows the REAR AXLE to shift slightly, breaking seal contact. Gear slipping under load is another common symptom, particularly during acceleration or when climbing grades, because the differential can no longer maintain proper tooth engagement. Abnormal whining or clunking noises from the transmission center section indicate that the cup spring has fatigued, allowing the DIFFERENTIAL HOUSING components to vibrate. Finally, erratic wheel speed behavior during turns suggests the spring can no longer control the preload on the TAPER ROLLER BEARING, leading to uneven torque distribution.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 5838.300.315 |
| Material | High-carbon spring steel (DIN 17221) |
| Outer Diameter | 58 mm |
| Inner Diameter | 30 mm |
| Free Height | 15.5 mm |
| Load Capacity | 4,200 N at 2.5 mm deflection |
| Weight | 0.045 kg |
| OEM Reference | ZF 5838.300.315 |
| Surface Treatment | Phosphate coated (anti-corrosion) |
Compatibility
This cup spring is specifically engineered for ZF’s WG100, WG130, and WG131 transmission models, which are commonly found in medium-duty trucks, agricultural tractors, and construction loaders. It also fits select variants of the WG180 and WG200 series when used in conjunction with the correct THRUST WASHER (5838300129) and THRUST WASHER (5838300130). Always verify your transmission’s serial number against ZF’s parts catalog, as minor design changes in the differential housing may require the 5838.300.315 for proper axial clearance.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 5838022003 | REAR AXLE | Transfers torque from differential to wheel hubs |
| 5838109001 | DIFFERENTIAL | Distributes power between left and right wheels |
| 0750117075 | TAPER ROLLER BEARING | Supports axial and radial loads on axle shafts |
| 5838300128 | DIFFERENTIAL HOUSING | Encloses and supports differential gear set |
| 0631329086 | SPRING PIN | Secures cup spring and thrust washers in position |
| 5838300129 | THRUST WASHER | Reduces friction between cup spring and housing |
| 5838300130 | THRUST WASHER | Secondary wear surface for axial load distribution |
| 5838300131 | AXLE BEVEL GEAR | Transfers rotation from driveshaft to differential |
| 5838300132 | COMPENS. STUB AXLE | Compensates for axle length variations |
| 5838300133 | COMPENS. STUB AXLE | Alternate compensation stub for specific ratios |
