Overview
The ZF 0634.402.105 R-RING is a precision-engineered sealing component designed exclusively for the WG 150 series transmission. This OEM genuine part functions as a critical static seal within the rotating assembly, preventing pressurized oil from bypassing the piston or clutch drum during gear engagement. Installed between the transmission housing and the rotating shaft, the R-Ring ensures hydraulic integrity under high-torque conditions. The SKU 0634.402.105 is the direct factory replacement, guaranteeing exact dimensional tolerances and material composition for long service life.
Symptoms of Failure
- External oil leaks near the bell housing: A worn R-Ring allows transmission fluid to escape past the seal, often leaving visible drips or wet spots on the housing exterior.
- Delayed or harsh gear engagement: Loss of hydraulic pressure due to a degraded R-Ring causes sluggish shifting or sudden clunks when selecting forward or reverse.
- Low transmission fluid level without visible external leaks: Internal bypassing of the R-Ring can route fluid into the torque converter cavity, leading to unexplained fluid loss and eventual overheating.
- Erratic clutch pack operation: Inconsistent pressure from a failing R-Ring results in intermittent slipping or shuddering during acceleration under load.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 0634.402.105 |
| Material | Nitrile rubber (NBR) with fabric reinforcement |
| Inner Diameter | 34.0 mm |
| Outer Diameter | 40.2 mm |
| Cross-Section Width | 4.0 mm |
| Weight | 0.008 kg |
| OEM Reference | ZF 0634.402.105 |
| Operating Temperature Range | -40°C to +120°C |
Compatibility
This R-Ring is engineered for the ZF WG 150 series, but it also fits select models in the WG 180 and WG 200 families where the same shaft seal diameter is used. It is commonly found in WG 150, WG 151, WG 180, and WG 200 transmissions installed in industrial forklifts, terminal tractors, and heavy-duty material handling equipment. Always verify the housing bore dimensions before installation.
Related Components
During replacement of the 0634.402.105 R-RING, it is recommended to inspect and replace the TRANSMISSION HOUSING (4642101108) and TRANSMISSION HOUSING (4642301208) if cracks or wear are present. The TYPE PLATE (0730365125) should be reattached after service, and the GROOVED STUD (0631311009) must be torqued to specification to prevent housing distortion.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4642101108 | TRANSMISSION HOUSING | Main structural casing for gear and shaft support |
| 4642301208 | TRANSMISSION HOUSING | Secondary housing for clutch and valve body |
| 0730365125 | TYPE PLATE | Identification plate with transmission serial number |
| 0631311009 | GROOVED STUD | Alignment dowel for housing assembly |
| 4642301168 | SCREEN SHEET | Fine mesh filter for oil return circuit |
| 4642301169 | SCREEN SHEET | Coarse mesh filter for suction line |
| 0636100621 | HEXAGON SCREW | Fastener for housing flange |
| 0630361029 | SEALING CAP | Plug for unused hydraulic ports |
| 4642306254 | ADAPTER | Interface plate for PTO or pump drive |
| 0634303340 | O-RING | Static seal for adapter plate |
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