Overview
The ZF 4699.309.073 PRESSURE DISK is a critical OEM genuine component engineered for the hydraulic control systems within ZF construction machinery transmissions. This precision-machined disk functions as a sealing and pressure-regulating element, ensuring that hydraulic fluid is directed accurately to activate clutch packs and gear sets. Positioned within the valve body or clutch housing assembly, the pressure disk maintains the necessary force to prevent internal cross-leakage and sustain consistent line pressure. The SKU 4699.309.073 is a direct replacement part that restores original transmission performance. For a complete assembly, this disk is often installed alongside the 4699101155 HOUSING and the 4699201018 HOUSING, which provide structural support and fluid routing.
Symptoms of Failure
When the ZF 4699.309.073 pressure disk wears out, operators will notice distinct performance issues. Transmission gear slipping under load is a primary symptom, as the disk can no longer maintain adequate hydraulic clamping force on clutch packs. Delayed or harsh gear engagement occurs when the disk fails to regulate pressure smoothly during shifts. Internal hydraulic oil leaks may develop, leading to low fluid levels and visible puddling around the transmission housing. Additionally, erratic shifting or loss of drive in specific gears can indicate that the disk is warped or scored, compromising its sealing surface. These failure modes are common in high-hour construction machinery operating in dusty or high-temperature environments.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4699.309.073 |
| Material | Hardened alloy steel with anti-corrosion coating |
| Outer Diameter | ~120 mm (estimated) |
| Inner Diameter | ~65 mm (estimated) |
| Thickness | ~8 mm (estimated) |
| Weight | ~0.35 kg (estimated) |
| OEM Reference | ZF 4699.309.073 |
| Surface Finish | Ground, Ra ≤ 0.8 µm |
Compatibility
This pressure disk is designed for use in ZF WG series transmissions commonly found in wheel loaders, graders, and heavy construction vehicles. It is compatible with the ZF WG180, WG200, and WG211 transmission models. The part also fits certain variants of the ZF 4WG-200 and 6WG-200 series. For proper installation, ensure the mating surfaces are clean and inspect the 4699309077 HOUSING COVER for cracks or wear. Secure the assembly using the correct 0636100132 TORX SCREW fasteners to achieve the specified torque.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4699101155 | HOUSING | Encloses clutch pack and routes hydraulic fluid |
| 4699201018 | HOUSING | Secondary housing for valve body support |
| 4699309077 | HOUSING COVER | Seals the transmission housing assembly |
| 0636100132 | TORX SCREW | High-tensile fastener for housing attachment |
| 0631302072 | CYLINDRICAL PIN | Alignment dowel for precise component positioning |
| 0634801038 | SEALING RING | Prevents fluid leakage between mating surfaces |
| 0636302013 | SCREW PLUG | Seals hydraulic test ports |
| 0501319149 | SCREW PLUG | Magnetic drain plug for debris collection |
| 0637101790 | BREATHER | Equalizes internal pressure and vents moisture |
| 0631302221 | CYLINDRICAL PIN | Secondary alignment pin for valve body |
