Overview
The ZF 0501.309.341 Reverse Ring is a critical internal component engineered for the planetary gearset within heavy-duty ZF transmissions. This OEM genuine part functions as a selective engagement mechanism, directing hydraulic pressure to lock or release the reverse clutch pack. Positioned within the valve body or clutch drum assembly, it ensures precise fluid routing during reverse gear operation. The SKU 0501.309.341 is manufactured to original ZF tolerances, guaranteeing a direct fit and restoring factory-specified shift timing. Without this ring, the transmission cannot establish the hydraulic circuit required for reverse motion, making it essential for any rebuild or overhaul of construction machinery gearboxes.
Symptoms of Failure
When the ZF 0501.309.341 Reverse Ring begins to wear or crack, operators will notice distinct performance degradation. The following failure modes are common:
- Delayed or harsh reverse engagement: A worn ring allows internal leakage, causing a lag of 2-4 seconds before reverse engages, often accompanied by a jarring clunk.
- Intermittent reverse gear slip under load: As the ring loses its sealing edge, the clutch pack fails to hold torque, resulting in RPM flare without corresponding vehicle movement, especially on inclines.
- Low reverse pressure readings: A cracked or distorted ring will cause a measurable drop in hydraulic pressure at the reverse clutch test port, typically falling below 150 psi (10.3 bar) at idle.
- Contaminated transmission fluid with metallic debris: Hardened ring material can fracture, shedding fine metallic particles into the oil, visible during routine filter inspections.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 0501.309.341 |
| OEM Reference | ZF 0501.309.341 (Genuine) |
| Outer Diameter | Approx. 85.0 mm (3.35 in) |
| Inner Diameter | Approx. 62.5 mm (2.46 in) |
| Thickness | 3.2 mm (0.126 in) |
| Material | Case-hardened steel (DIN 1.7131) |
| Weight | 0.045 kg (0.10 lbs) |
| Surface Finish | Ground & polished sealing face |
Compatibility
This Reverse Ring (0501.309.341) is designed for use in ZF’s modular powershift transmission series commonly deployed in construction machinery. It is a direct replacement part for the following transmission models:
- ZF WG180 (all variants, including WG180-1 and WG180-2)
- ZF WG200 (standard and high-torque versions)
- ZF WG120 (early production models with reverse clutch pack)
- ZF 4WG-200 (four-speed powershift units)
- ZF 5WG-200 (five-speed variants requiring reverse ring update)
Always verify the internal clutch pack configuration before installation. This ring is not interchangeable with forward clutch rings due to differences in groove depth and sealing diameter. For applications in wheel loaders, graders, and dozers, confirm the transmission serial number against ZF technical bulletins.
