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Porsche > 996 (911) (1997-2005) > 996 C4 3.4L 1997-08/01 > Gearbox / Transmission > Gearbox Parts >

Driveshaft Flange

DISPLAYING 1 to 2 (of 2 products)
Round Seal For Flanged Shaft, (Tiptronic Transmission). Porsche 986 / 987 / 996 1998-08 - 98639703400
2
Round Seal For Flanged Shaft, (Tiptronic Transmission). Porsche 986 / 987 / 996 1998-08
Special Order item
98639703400
Product Information
Product Information
Round Seal For Flanged Shaft, (Tiptronic Transmission).
The Porsche Round Seal for Flanged Shaft is a genuine OEM component engineered for vehicles equipped with the Tiptronic transmission. Positioned at the flanged/intermediate shaft housing, this seal prevents automatic transmission fluid (ATF) from leaking while keeping dirt and moisture from entering the transmission assembly.

Fits:
  • Porsche Boxster 986 2.7L 1999-00
  • Porsche Boxster S 986 3.2L 1999-00
  • Porsche Boxster 987 2.7L 2005 -08/08
  • Porsche Boxster 987 S 3.2/3.4L 2005-08/08
  • Porsche Cayman 2.7L 987C 2006-08
  • Porsche Cayman S 3.4L 987C 2005-08
  • Porsche 996 C2 3.4L 1997-08/01
  • Porsche 996 C4 3.4L 1997-08/01
  • Porsche 996 C2 3.6L 09/01-2005
  • Porsche 996 C4 3.6L 09/01-2005
  • Porsche 996 C4S 3.6L 09/01-2005

Cars With Option Codes:
249 - Tiptronic Transmission

What This Product Does:

  • It seals the interface between the intermediate / flanged shaft and the transmission housing, preventing fluid (transmission oil / ATF) from leaking out.
  • Maintains the internal fluid pressure and lubrication inside the Tiptronic transmission / differential system.
  • Prevents external contaminants (dirt, water) from entering the transmission via that junction.
  • Helps ensure the correct fluid environment, which is critical for gears, bearings and internal transmission components to remain lubricated and cool.

Symptoms Of A Worn / Failed Seal:
  • Transmission fluid leaks (ATF / transaxle oil) around the area of the intermediate shaft or housing joint.
  • Low transmission / transaxle fluid levels over time.
  • Whining, gear noise or increased operating temperature if lubrication is compromised.
  • Slipping, harsh shifts, or degraded Tiptronic performance when fluid levels or pressure are affected.
  • Oil staining or wetness on the underside of the car or near the transmission.
  • Possibly visible damage to the seal (cracks, deformations) or misalignment in the shaft / flange area.

Why Replacement Matters:
  • Ensures fluid integrity and pressure inside the transmission—without a proper seal the system can lose fluid or allow contamination.
  • Protects internal transmission components (gears, bearings, clutches) from insufficient lubrication or contamination.
  • Prevents costly damage from running low on fluid or letting debris in.
  • Avoids slipping, erratic shifting, or even transmission failure.

Diagram Ref No 6



Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

98639703400
98639703400

The product you are viewing cross references to these numbers
Seal For Differential Output Shaft Flange For Porsche 986/987-1 Boxster & Cayman / 996-1 Carrera 3.4L (Tiptronic Gearbox) - 99639701500
3
Seal For Differential Output Shaft Flange For Porsche 986/987-1 Boxster & Cayman / 996-1 Carrera 3.4L (Tiptronic Gearbox)
Special Order item
99639701500
Product Information
Product Information
Oil Seal For The Long Differential Output Shaft Flange, Located On The Side Of The Gearbox Without The Differential Cover Plate. 

Outer Diameter: 54mm. 

Fits:
Vehicles With Tiptronic Transmission (PR 249)
Porsche 986 Boxster 1997>>2004

Porsche 987.1 Boxster MKI 2005>>2008
Porsche 987.1 Cayman 2006>>2008

Porsche 996 Carrera 3.4L 1998>>2001

Diagram Ref No 3

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99639701500
99639701500

The product you are viewing cross references to these numbers
DISPLAYING 1 to 2 (of 2 products)
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About Driveshaft Flange

Porsche Driveshaft Flanges - Essential Gearbox Connection Components

Porsche driveshaft flanges are critical drivetrain components that connect the driveshafts to the gearbox or differential, allowing engine power to be transferred smoothly to the wheels. Precision-engineered for strength and alignment, these flanges play a vital role in maintaining drivetrain stability, torque delivery, and long-term gearbox reliability.

Available from Design911, Porsche driveshaft flanges are supplied to meet OEM specifications, making them ideal for maintenance, repairs, and performance rebuilds where drivetrain integrity is essential.

What Does a Porsche Driveshaft Flange Do?

The driveshaft flange acts as the mechanical interface between the gearbox output and the driveshaft.

Core Functions:

  • Transfers engine torque from the gearbox to the driveshaft
  • Maintains precise alignment within the drivetrain
  • Supports smooth power delivery under acceleration and load
  • Absorbs rotational forces during gear changes
  • Ensures reliable connection between drivetrain components

Without a correctly functioning driveshaft flange, drivetrain vibration and component wear rapidly increase.

Why Do Driveshaft Flanges Fail?

Driveshaft flanges operate under constant rotational load and are subject to wear over time.

Common Causes of Failure:

  • Metal fatigue from high mileage or aggressive driving
  • Worn splines due to poor lubrication or age
  • Corrosion from moisture ingress
  • Excessive drivetrain vibration or misalignment
  • Increased torque loads from performance upgrades

Failure can lead to knocking noises, vibration under acceleration, oil leaks, or complete drivetrain disengagement.

When Should a Driveshaft Flange Be Replaced?

A Porsche driveshaft flange should be inspected and replaced if any of the following symptoms occur:

  • Visible wear or damage to splines
  • Excessive play or looseness in the drivetrain
  • Oil leakage from the gearbox flange seal
  • Clunking or vibration during acceleration
  • During gearbox rebuilds or clutch replacements

Preventative replacement during gearbox servicing can help avoid costly drivetrain damage.

Highlights

  • Essential Porsche gearbox-to-driveshaft connection component
  • Maintains drivetrain alignment and torque transfer
  • Manufactured to OEM specifications
  • Ideal for maintenance, repairs, and rebuilds
  • Helps eliminate vibration and premature drivetrain wear

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