Overview
The ZF 0501.313.402 DRAIN VALVE is a critical fluid management component engineered for the WG100, WG130, and WG131 transmission series. This OEM genuine part serves as the primary extraction point for transmission oil during routine service intervals, ensuring complete evacuation of spent lubricant from the sump. Located on the lower pan or housing section, the 0501.313.402 valve integrates directly with the 4108101093 HOUSING and 4108201177 HOUSING to maintain a sealed fluid circuit. Precision-machined to ZF tolerances, this drain valve prevents cross-threading and galling, which are common issues with aftermarket substitutes. The SKU 0501.313.402 is factory-tested for burst pressure resistance and corrosion protection, making it a direct replacement for worn or damaged units in heavy-duty driveline applications.
Symptoms of Failure
- Persistent oil seepage around the transmission pan: A degraded 0501.313.402 valve seal allows fluid to weep past the threads, leaving visible drips on the housing or ground beneath the vehicle. This is often misdiagnosed as a pan gasket failure.
- Incomplete fluid drainage during service: When the valve seat becomes pitted or contaminated with debris, the drain port fails to open fully, trapping old oil in the sump and accelerating transmission wear.
- Stripped or cross-threaded valve body: Repeated overtightening or thermal cycling can deform the valve threads, making it impossible to secure the 0636302056 SCREW PLUG properly. This leads to sudden oil loss under pressure.
- Gear engagement hesitation or slipping: A leaking drain valve reduces hydraulic pressure in the valve body, causing delayed shifts or clutch pack slippage, particularly under load.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 0501.313.402 |
| Material | Steel with zinc-nickel plating |
| Overall Length | 42 mm |
| Thread Size | M22 x 1.5 |
| Hex Size | 19 mm |
| Weight | 0.08 kg |
| OEM Reference | ZF 0501.313.402 |
| Max Operating Pressure | 12 bar |
| Temperature Range | -40°C to +120°C |
Compatibility
This drain valve is specifically designed for ZF WG-series transmissions, including the WG100, WG130, and WG131 models. It also fits select variants of the WG180 and WG200 series when used with the correct 4108301304 BEARING COVER adapter. The 0501.313.402 is not compatible with ZF Ecomat or AS Tronic series without a housing modification. Always verify thread pitch and seat depth against your transmission’s service manual before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4108101093 | HOUSING | Main transmission casing for WG series |
| 4108201177 | HOUSING | Rear housing section for torque converter |
| 0636302056 | SCREW PLUG | Seals the drain valve port during operation |
| 4108301304 | BEARING COVER | Protects output shaft bearing assembly |
| 4108306173 | GASKET | Seals the drain valve to housing interface |
| 0750110040 | SHAFT SEAL | Prevents oil leakage at rotating shafts |
| 4108111051 | POWER TAKE-OFF | Drives auxiliary hydraulic equipment |
| 0730106757 | WASHER | Flat washer for valve mounting |
| 0730106758 | WASHER | Lock washer for vibration resistance |
| 0730106759 | WASHER | Sealing washer for drain plug |
