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Porsche // 996 (911) (1997-2005) // 996 C4S 3.6L 09/01-2005
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Lock nut for transmission main shaft. Porsche 911 72-89 / 964 / 993 / 996 turbo / 997 turbo / GT3 - 99903403300
99903403300
Vehicle Group
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
- Porsche 993 (911) TURBO 1994-96
- Porsche 993 (911) GT2 1994-97
- Porsche 993 (911) TURBO S 1994-97
- Porsche 996 TURBO 2000-05
- Porsche 996 GT2 2001-05
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT3 / GT3 RS 2007-09
- Porsche 997 MK1 GT2 2007-09
- Porsche 997 MKII GT3 / GT3 RS 2010-11
- Porsche 997 MKII Turbo 2010-13
- Porsche 997 MKII GT2 RS 2011-13
Information
Lock nut for transmission pinion shaft - M30 x 1.5
The Genuine Porsche 99903403300 transmission pinion shaft lock nut is an OE M30 x 1.5 shouldered lock nut for selected Porsche manual gearbox applications, including 911 1972–1989, 964, 993, 996 Turbo, 997 Turbo and GT3 models. It secures key transmission shaft components and is ideal for gearbox rebuilds, transmission repairs or restoration using Genuine Porsche hardware.
Sold individually
Fits:
Porsche 911 - 1972 to 1989 (915 and G50)
Porsche 964 - 1989 to 1994
Porsche 993 - 1994 to 1994
Porsche 996 turbo - 2001 to 2005
Porsche 997 turbo - 2007 to 2013
Porsche 996 GT3 - 2003 to 2005
Porsche 997 GT3 - 2007 to 2011
Manual transmission
Diagram ref no 20
This nut is used in selected Porsche manual gearbox assemblies, including 915, G50 and later Turbo / GT gearbox applications where specified.
What This Part Does / Functions
• Secures transmission shaft components in position
• Helps maintain correct gearbox shaft assembly preload and alignment
• Supports proper operation of the pinion shaft / main shaft assembly
• Helps prevent loosening under drivetrain load and vibration
• Provides correct OE Porsche M30 x 1.5 thread and shouldered nut design
• Replaces a worn, damaged, previously removed or incorrectly reused lock nut
• Supports correct transmission rebuild and gearbox service procedures
• Maintains factory Porsche gearbox hardware specification.
Why Replace This Part?
Transmission lock nuts are critical gearbox fasteners. During gearbox rebuilds or shaft service, the original nut may be removed, disturbed, damaged or no longer suitable for reuse. A worn, distorted or incorrectly secured shaft nut can affect gearbox assembly, shaft retention and long-term reliability. Replacing it with a Genuine Porsche OE transmission shaft lock nut helps ensure the gearbox is rebuilt using the correct factory-specified hardware.
When to Replace This Part
• During manual gearbox rebuild or overhaul
• When servicing the transmission main shaft or pinion shaft
• If the original nut is worn, damaged, distorted or corroded
• If the nut has been removed during gearbox disassembly
• During differential, gear set or shaft bearing replacement
• If the original lock nut no longer secures correctly
• When restoring a Porsche gearbox with correct OE hardware
• Whenever Porsche workshop procedure recommends replacement after removal.
Where It Fits on the Car
This lock nut fits inside the manual transmission / gearbox assembly. It is used on the transmission main shaft or pinion shaft, depending on the gearbox type and application.
Installation requires correct Porsche gearbox tools, torque procedure and workshop specifications. This is a specialist transmission component and should be fitted by an experienced Porsche gearbox technician.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99903403300
The product you are viewing cross references to these numbers
The Genuine Porsche 99903403300 transmission pinion shaft lock nut is an OE M30 x 1.5 shouldered lock nut for selected Porsche manual gearbox applications, including 911 1972–1989, 964, 993, 996 Turbo, 997 Turbo and GT3 models. It secures key transmission shaft components and is ideal for gearbox rebuilds, transmission repairs or restoration using Genuine Porsche hardware.
Sold individually
Fits:
Porsche 911 - 1972 to 1989 (915 and G50)
Porsche 964 - 1989 to 1994
Porsche 993 - 1994 to 1994
Porsche 996 turbo - 2001 to 2005
Porsche 997 turbo - 2007 to 2013
Porsche 996 GT3 - 2003 to 2005
Porsche 997 GT3 - 2007 to 2011
Manual transmission
Diagram ref no 20
This nut is used in selected Porsche manual gearbox assemblies, including 915, G50 and later Turbo / GT gearbox applications where specified.
What This Part Does / Functions
• Secures transmission shaft components in position
• Helps maintain correct gearbox shaft assembly preload and alignment
• Supports proper operation of the pinion shaft / main shaft assembly
• Helps prevent loosening under drivetrain load and vibration
• Provides correct OE Porsche M30 x 1.5 thread and shouldered nut design
• Replaces a worn, damaged, previously removed or incorrectly reused lock nut
• Supports correct transmission rebuild and gearbox service procedures
• Maintains factory Porsche gearbox hardware specification.
Why Replace This Part?
Transmission lock nuts are critical gearbox fasteners. During gearbox rebuilds or shaft service, the original nut may be removed, disturbed, damaged or no longer suitable for reuse. A worn, distorted or incorrectly secured shaft nut can affect gearbox assembly, shaft retention and long-term reliability. Replacing it with a Genuine Porsche OE transmission shaft lock nut helps ensure the gearbox is rebuilt using the correct factory-specified hardware.
When to Replace This Part
• During manual gearbox rebuild or overhaul
• When servicing the transmission main shaft or pinion shaft
• If the original nut is worn, damaged, distorted or corroded
• If the nut has been removed during gearbox disassembly
• During differential, gear set or shaft bearing replacement
• If the original lock nut no longer secures correctly
• When restoring a Porsche gearbox with correct OE hardware
• Whenever Porsche workshop procedure recommends replacement after removal.
Where It Fits on the Car
This lock nut fits inside the manual transmission / gearbox assembly. It is used on the transmission main shaft or pinion shaft, depending on the gearbox type and application.
Installation requires correct Porsche gearbox tools, torque procedure and workshop specifications. This is a specialist transmission component and should be fitted by an experienced Porsche gearbox technician.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99903403300
99903403300
91530228100
The product you are viewing cross references to these numbers
Price: £19.73
In stock
Related products
Vehicle Group
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- 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
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
Information
Shaft Sealing Ring. 40 x 62 x 10.
Fits:
Porsche 996 C4 / C4S 1998-05
Porsche 996 Turbo 2001-05
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911347540
The product you are viewing cross references to these numbers
Fits:
Porsche 996 C4 / C4S 1998-05
Porsche 996 Turbo 2001-05
Diagram ref no 3.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911347540
99911347540
The product you are viewing cross references to these numbers
Price: £28.45
In stock
Vehicle Group
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- 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
- Porsche 996 TURBO 2000-05
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
Information
Oil pan gasket.
Fits:
Porsche 986 Boxster 1997-04 Tiptronic
Porsche 987 Boxster 2005-08 Tiptronic
Porsche 987C Cayman 2007>> Tiptronic
Porsche 996 1998-05 Tiptronic
Click 'Zoom in' for large parts diagram.
Diagram ref no 2
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
98639701600
The product you are viewing cross references to these numbers
Fits:
Porsche 986 Boxster 1997-04 Tiptronic
Porsche 987 Boxster 2005-08 Tiptronic
Porsche 987C Cayman 2007>> Tiptronic
Porsche 996 1998-05 Tiptronic
Click 'Zoom in' for large parts diagram.
Diagram ref no 2
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
98639701600
98639701600
634.061
The product you are viewing cross references to these numbers
Price: £36.36
In stock
Vehicle Group
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster S 986 3.2L 2003-04
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
- Porsche 993 (911) TURBO 1994-96
- Porsche 993 (911) GT2 1994-97
- Porsche 993 (911) TURBO S 1994-97
- 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
- Porsche 996 TURBO 2000-05
- Porsche 996 GT2 2001-05
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 968 CS 3.0L 1993-95
Information
Differential output shaft seal. 48 x 68 x 10 mm.
Fits:
Porsche 911 Carrera 3.2L 1984-89
Porsche 911 Turbo 3.3 1978-89
Porsche 964 1989-94
Porsche 993 1995-98
Porsche 996 1998-05
Porsche 986 Boxster 3.2L 2000-04
Porsche 986 968CS 1993-95
Click 'Zoom in' for large parts diagram.
Diagram ref no 20
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911334741
The product you are viewing cross references to these numbers
Fits:
Porsche 911 Carrera 3.2L 1984-89
Porsche 911 Turbo 3.3 1978-89
Porsche 964 1989-94
Porsche 993 1995-98
Porsche 996 1998-05
Porsche 986 Boxster 3.2L 2000-04
Porsche 986 968CS 1993-95
Click 'Zoom in' for large parts diagram.
Diagram ref no 20
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911334741
99911334740
99911334741
The product you are viewing cross references to these numbers
Price: £25.45
In stock
Vehicle Group
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster S 986 3.2L 2003-04
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) RS 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
- Porsche 993 (911) TURBO 1994-96
- Porsche 993 (911) GT2 1994-97
- Porsche 993 (911) TURBO S 1994-97
- 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
- Porsche 996 TURBO 2000-05
- Porsche 996 GT2 2001-05
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 968 CS 3.0L 1993-95
Information
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.
Sold each.
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
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911334741
The product you are viewing cross references to these numbers
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.
Sold each.
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
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911334741
99911334740
99911334741
The product you are viewing cross references to these numbers
Price: £11.50
In stock