OVERVIEW
Factory 13 x 2 seal for the assigned hydraulic connection
N-903-056-01 is the Genuine VW/Audi 13 x 2 O-ring used at the specific transmission-control and convertible-roof hydraulic assembly positions listed below. Its size must match the original sealing groove and mating component.
O-rings seal through controlled compression in a correctly prepared groove. A seal with a similar appearance can have a different section or material specification, so match the complete factory number and application before installation.
Technical details
- Complete factory number: N-903-056-01.
- Factory specification: 13 x 2 mm.
- Design: circular-section elastomer O-ring.
- Quantity supplied: one individual O-ring.
The catalog size identifies a 13 mm nominal inside diameter and 2 mm cross-section. Use this genuine application-specific seal rather than selecting an unspecified generic rubber ring by size alone.
Common reasons to replace
- The original seal is cut, nicked or pinched.
- The ring has hardened, flattened or lost its original shape.
- Fluid leakage is traced to the assigned sealed connection.
- The assembly has been opened and the repair procedure requires a new seal.
Check the groove and mating surfaces for scratches, contamination and corrosion. Replacing an O-ring does not correct damaged sealing surfaces, a worn component or a fault elsewhere in the hydraulic system.
Vehicle fitment
This seal is used in different assemblies. The table identifies the confirmed vehicle and original sealing position; confirm both before ordering.
| Vehicle | Model years | Engine | Configuration | Application restrictions |
|---|---|---|---|---|
| Audi A8 | 2000, 2002 | 4.2L gasoline V8 | D2 sedan; standard or long wheelbase; quattro; 5-speed automatic transmission control / valve-body assembly | Original 13 x 2 O-ring location assigned N90305601; match the installed transmission and sealing position. |
| Audi S8 | 2002 | 4.2L gasoline V8 | D2 sedan; quattro; 5-speed automatic transmission control / valve-body assembly | Original 13 x 2 O-ring location assigned N90305601; match the installed transmission and sealing position. |
| Audi Cabriolet | 1995 | 2.8L gasoline V6 | Type 8G convertible; Assigned convertible-roof hydraulic assembly sealing position | Match original 13 x 2 O-ring location; not interchangeable with the neighboring 11 x 2, 12 x 2 or 19 x 2 seals. |
Installation guidance
Follow the factory procedure for the exact transmission or roof hydraulic assembly. Release pressure and support components as prescribed, clean the groove and fit the seal without twisting or stretching it. Use only the specified assembly lubricant or system fluid.
Reassemble to the prescribed specification and complete the required filling, bleeding and functional checks. Inspect the repaired connection for leakage before returning the system to service.
Ordering information
Sold individually as one genuine O-ring. Hydraulic components, valve body, fluid and other seals are separate. Confirm the original factory number, sealing position and required quantity.