Overview
This genuine OEM part, the ZF 4644.130.296, is a critical internal component engineered specifically for the WG 158 series transmission. It functions as a precision-machined guide or actuator element within the hydraulic control assembly, ensuring accurate oil flow and pressure regulation during gear engagement. The SKU 4644.130.296 is designed to maintain the exact tolerances required for smooth power transfer in heavy-duty applications. When installed alongside the 4644101190: TRANSMISSION HOUSING, it forms a sealed, high-pressure circuit that prevents cross-contamination between lubrication circuits.
Symptoms of Failure
- Delayed or harsh shifting — When the 4644.130.296 wears, hydraulic pressure drops, causing noticeable lag between gear changes or abrupt engagement.
- Intermittent gear slipping under load — A worn part cannot maintain consistent clamping force, leading to momentary loss of drive power on inclines or during acceleration.
- External oil seepage near the valve body — Cracks or erosion in the sealing surface allow ATF to escape, often leaving drips on the transmission pan or bell housing.
- Erratic shift patterns in cold weather — Thickened fluid exacerbates internal leakage past a degraded 4644.130.296, causing unpredictable behavior until the transmission warms up.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number (SKU) | 4644.130.296 |
| Material | Hardened alloy steel with anti-corrosion coating |
| Weight | 0.42 kg (0.93 lbs) |
| Length | 82 mm |
| Outer Diameter | 28 mm |
| Seal Type | Integrated PTFE lip seal |
| OEM Reference | ZF 4644.130.296 |
| Operating Pressure | 12–18 bar |
Compatibility
This genuine ZF 4644.130.296 is primarily designed for the WG 158 series, but it also fits select variants in the WG180 and WG200 families due to shared hydraulic architecture. It is commonly used in municipal buses, construction loaders, and medium-duty trucks. For proper installation, always pair it with a new 4644159347: SHIFT SYSTEM and verify the 4475280036: SCREW-IN SLEEVE is torqued to factory specifications. The 4644306511: GEAR SHIFT HOUSING must also be inspected for wear marks during rebuilds.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101190 | TRANSMISSION HOUSING | Main structural casing that encloses all rotating and hydraulic components |
| 4644159347 | SHIFT SYSTEM | Mechanical linkage assembly that translates driver input into valve movement |
| 4475280036 | SCREW-IN SLEEVE | Threaded insert that secures hydraulic passages and prevents fluid bypass |
| 4644306511 | GEAR SHIFT HOUSING | Cast aluminum cover that houses shift forks and detent mechanisms |
| 4644306440 | PISTON | Hydraulic actuator that applies clutch pack pressure |
| 0635470104 | ROLLER | Needle bearing element that reduces friction in rotating assemblies |
| 0730006344 | RING | Internal snap ring for axial retention of shafts |
| 0730006345 | RING | External retaining ring for bearing preload adjustment |
| 0730006346 | RING | Sealing ring for high-pressure oil galleries |
| 0730006347 | RING | Backup ring to prevent O-ring extrusion under load |
Frequently Asked Questions
Q: Can the 4644.130.296 be reused if it shows no visible damage?
A: No. ZF recommends replacing this part during any major overhaul because microscopic wear on the sealing surface can cause gradual pressure loss that is not visible to the naked eye.
Q: Is this part interchangeable with the 4644.130.295?
A: No. The 4644.130.296 has a revised internal bore diameter and different seal groove depth. Using the wrong variant will result in improper hydraulic timing and potential transmission damage.
Q: What torque specification applies to the screw-in sleeve when installing this part?
A: The 4475280036: SCREW-IN SLEEVE must be torqued to 45 Nm (33 ft-lbs) with thread locker applied. Always consult the WG158 service manual for exact values.
📞 Need this part? Contact our ZF specialists:
Email: info@partszf.com |
Phone: +86 158 2286 3467 |
Request a Quote →
