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99970738840
Product Information
Product Information
O-ring for gearbox oil cooler ATF
This Porsche Genuine OE O-Ring for Gearbox Oil Cooler ATF is a precision-engineered sealing ring used within the automatic (Tiptronic) transmission cooling system. This small but critical component provides a fluid-tight seal between the gearbox oil cooler and connecting pipework.
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Fits:
Porsche 986 Boxster 1997 - 2004 Tiptronic
Porsche 987.1 Boxster 2005 - 2007 Tiptronic
Porsche 987C.1 Cayman 2007 - 2008 Tiptronic
Porsche 996 C2 / C4  / Turbo 1998 - 2005 Tiptronic
Porsche 997.1 C2 / C4  2005 - 2008 Tiptronic

Diagram ref no 2

Manufactured to Porsche OE standards, it ensures correct dimensions, material quality, and resistance to ATF (automatic transmission fluid), heat, and pressure.

This O-ring seals the junction between the gearbox oil cooler (heat exchanger) and its associated pipes, preventing ATF leaks and maintaining correct system pressure. By ensuring a secure seal, it allows the transmission fluid to circulate properly through the cooler, helping regulate temperature and maintain optimal gearbox performance.

Functions & Technical Role
•  Fluid sealing: Prevents ATF leaks at oil cooler connections
  Pressure retention: Maintains correct hydraulic pressure within the system
•  Thermal resistance: Designed to withstand high transmission temperatures
•  System protection: Prevents contamination and air ingress
•  OEM precision fit: Exact size and material specification for Porsche applications

Fitment / Position on car
  Fitting position: Transmission cooling system
  Location: Between gearbox oil cooler (ATF heat exchanger) and fluid pipes
  System: Automatic transmission (Tiptronic) lubrication and cooling

Although small, O-rings are critical wear items exposed to heat cycles, pressure, and fluid degradation. Over time they can harden, shrink, or crack, leading to:
  ATF leaks around the gearbox oil cooler
  Loss of transmission fluid and pressure
  Overheating of the gearbox
  Potential transmission damage

Replacing with a genuine Porsche OE O-ring ensures proper sealing, reliability, and long-term protection of the transmission system.

Related reference numbers
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99970738840
99970738840

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