Overview
The ZF 0501.221.351 CUT-OFF VALVE is a critical pneumatic control component designed for the WG100, WG130, and WG131 transmission series. This OEM genuine part precisely regulates the flow of compressed air to the clutch and range-change actuators, ensuring smooth gear engagement and reliable shift timing. Positioned within the valve body assembly, the SKU 0501.221.351 acts as a gatekeeper, cutting off air supply when the transmission is in neutral or during specific shift sequences to prevent driveline damage. When paired with the 4663101003: HOUSING and 4663301026: COVER, this valve forms a sealed pneumatic circuit essential for heavy-duty commercial vehicle operation.
Symptoms of Failure
- Delayed or harsh gear engagement: A worn cut-off valve causes sluggish clutch application, leading to grinding or clunking sounds during shifts.
- Air leaks at the valve body: Visible hissing or oil mist around the valve area indicates internal seal degradation, often accompanied by reduced system pressure.
- Transmission stuck in neutral: When the valve fails to close properly, the transmission may refuse to engage a gear, stranding the vehicle.
- Erratic range shifting: Intermittent failure to shift between high and low range, especially under load, points to a malfunctioning cut-off valve.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number (SKU) | 0501.221.351 |
| Type | Pneumatic Cut-Off Valve |
| Material | Anodized Aluminum Body with Brass Core |
| Operating Pressure | 8–12 bar (116–174 psi) |
| Port Size | G1/4″ (BSPP) |
| Weight | 0.35 kg (0.77 lbs) |
| OEM Reference | ZF 0501.221.351 |
| Seal Material | NBR (Nitrile Rubber) |
Compatibility
This cut-off valve is engineered for ZF WG series transmissions, specifically the WG100, WG130, and WG131 models. It also fits select WG180 and WG200 variants when used with the correct 0631306816: CYLINDRICAL PIN and 0636100817: CAP SCREW for mounting. Always verify your transmission serial number against the ZF parts catalog to ensure proper fitment. The valve is not compatible with older WG80 or WG90 series without adapter kits.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4663101003 | HOUSING | Encloses the valve assembly and directs airflow |
| 4663301026 | COVER | Seals the housing and protects internal components |
| 0631306816 | CYLINDRICAL PIN | Aligns valve components during assembly |
| 0636100817 | CAP SCREW | Secures the cover to the housing |
| 4656301148 | FIXING PLATE | Provides additional mounting stability |
| 4475280099 | SCREW PLUG | Seals unused ports in the valve body |
| 0634303266 | O-RING | Prevents air leaks at the valve base |
| 4475280018 | SCREW PLUG | Alternate port plug for different configurations |
| 0634303312 | O-RING | Seals the cover-to-housing interface |
| 0501325243 | TEMP.SENSOR | Monitors transmission fluid temperature |
