Differential output shaft seal. Porsche 911 / 964 / 993 / 996 / 986 Boxster / 968  ❭  99911334741

Differential output shaft seal. 48 x 68 x 10 mm.
OE Match differential output shaft seal, engineered to replicate the original Porsche component that seals the output shaft on the differential housing. It prevents gear oil from leaking out where the drive axles exit the differential - a critical sealing function in the drivetrain system.
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Fits:
Porsche 911 Carrera 3.2L 1984 - 1989
Porsche 911 Turbo 3.3 1978 - 1989
Porsche 964 1989 - 1994
Porsche 993 1995 - 1998
Porsche 996 1998 - 2005
Porsche 986 Boxster 3.2L 2000 - 2004
Porsche 986 968CS 1993 - 1995

Diagram ref no 20

The differential output shaft seal creates a pressure-resistant, low-friction barrier around the rotating driveshaft or axle stub where it exits the differential. It prevents differential oil from escaping the gearbox while allowing rotational movement, helping maintain optimal lubrication of internal gears, bearings, and limited-slip components.

Function: Installed in the differential carrier housing at the output flange, the seal’s elastomer lip bears against the rotating shaft surface, maintaining contact under variable engine speed, gear torque, and temperature conditions. The internal garter spring ensures the lip is held in consistent contact with the shaft surface, helping prevent weeping or drips that can lead to low lubricant levels and accelerated drivetrain wear.

A worn or hard differential output seal can lose its effectiveness over time, leading to leaks, oil drips, and reduced gear oil levels in the differential. Low lubricant can accelerate wear of differential bearings, gears, and limited-slip clutches - ultimately causing expensive internal damage. Replacing the seal with an OE Match component helps preserve proper differential lubrication, reduces contamination of nearby brake and suspension parts with oil, and maintains drivetrain longevity and performance.

When to replace:
• Visible gear oil leakage from the differential area
•  Oil accumulating near the rear of the gearbox or under the car
•  During differential service or rebuild
•  After replacing output shafts/axle flanges
•  Preventive maintenance on high-mile vehicles

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