Overview
The ZF 0634.402.526 R-RING is a critical OEM sealing component engineered specifically for the WG260 heavy-duty transmission. This precision-machined ring sits within the rotating clutch drum assembly, where it functions as a dynamic seal between high-pressure hydraulic circuits and the transmission housing. By maintaining a tight barrier against fluid bypass, the 0634.402.526 ensures consistent clutch engagement pressure and prevents cross-contamination between oil galleries. As an original ZF part, this R-RING is manufactured to exacting tolerances that aftermarket seals cannot replicate, making it essential for maintaining factory-specified transmission performance in construction machinery applications.
Symptoms of Failure
When the ZF 0634.402.526 R-RING begins to wear, operators typically notice three distinct failure indicators. First, internal hydraulic pressure loss manifests as delayed or soft gear engagement, particularly when shifting into forward or reverse under load. Second, erratic clutch modulation occurs as the worn ring allows pressurized oil to bleed past the seal, causing the transmission to hunt between gears during operation. Third, visible oil seepage from the transmission bell housing or around the clutch drum access cover often accompanies R-RING degradation, leaving telltale drips on the undercarriage after extended idle periods. Left unaddressed, a failing 0634.402.526 can lead to complete clutch pack failure and costly internal damage to the 4646101028: TRANSMISSION HOUSING.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number | 0634.402.526 |
| Type | R-Ring (Rotary Seal Ring) |
| Material | Nitrile Rubber (NBR) with PTFE backup |
| Inner Diameter | 34.0 mm |
| Outer Diameter | 40.2 mm |
| Cross-Section | 2.6 mm |
| Weight | 0.012 kg |
| OEM Reference | ZF 0634.402.526 |
| Hardness | Shore A 85 ±5 |
| Operating Temp | -40°C to +120°C |
Compatibility
This R-RING is a direct-fit component for the ZF WG260 powershift transmission series, commonly found in wheel loaders, graders, and material handlers from leading construction OEMs. Based on its dimensional profile and sealing application, the 0634.402.526 is also compatible with the following ZF transmission models that share the same clutch drum architecture: WG180, WG200, and WG250. When replacing this seal, it is standard practice to also inspect the 4646301095: HOUSING for scoring or wear, and to replace the 4646301087: COVER gasket simultaneously. Secure the assembly using the correct 0636015304: HEXAGON SCREW torque specifications to prevent future leaks.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4646101028 | TRANSMISSION HOUSING | Main structural casing for gear and clutch assembly |
| 4646301095 | HOUSING | Intermediate housing for clutch drum support |
| 4646301087 | COVER | Access cover sealing the clutch drum cavity |
| 0636015304 | HEXAGON SCREW | Fastener for cover and housing retention |
| 0636101828 | CAP SCREW | High-torque fastener for clutch pack retention |
| 4646301102 | COVER SHEET | Thin shim for adjusting clutch clearance |
| 4646301098 | COVER SHEET | Alternate thickness shim for clutch stack |
| 0730365125 | TYPE PLATE | Identification plate for transmission model |
| 0631311009 | GROOVED STUD | Alignment stud for housing positioning |
| 0636101193 | CAP SCREW | Fastener for oil pump mounting |
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