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Lock nut for transmission main shaft. Porsche 911 72-89 / 964 / 993 / 996 turbo / 997 turbo / GT3 › 99903403300
- 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
This OE Match transmission pinion shaft lock nut is a replacement M30 x 1.5 retaining nut used within the gearbox assembly. It is designed to match the original-style fitment and function, helping ensure the pinion shaft is secured to the correct specification.
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
The lock nut secures the transmission pinion shaft within the gearbox assembly. Correct retention of the pinion shaft is essential for maintaining drivetrain alignment, gear mesh, bearing preload, and reliable transmission operation.
Functions
• Replaces the transmission pinion shaft lock nut
• Secures the pinion shaft within the gearbox
• Supports correct gear mesh and drivetrain alignment
• Helps maintain bearing preload where applicable
• Used during gearbox rebuild, pinion shaft service, or transmission repair
• Replaces worn, damaged, rounded, corroded, or previously removed lock nuts
• OE Match replacement for Porsche transmission service.
Why Replace This Part?
Transmission lock nuts are highly loaded retaining components and may be damaged during removal, lose locking integrity, or show thread wear over time. Reusing a worn or damaged lock nut can compromise correct pinion shaft retention and may affect gearbox setup. Replacement is recommended during gearbox overhaul or whenever the lock nut has been removed.
When to Replace This Part
• Gearbox or transmission rebuild is being carried out
• The pinion shaft has been removed or serviced
• The original lock nut is rounded, corroded, damaged, or worn
• Thread condition is poor or uncertain
• Gear mesh, bearing preload, or transmission setup is being checked
• Preventative replacement is required during major drivetrain service
• The vehicle is undergoing Porsche gearbox restoration.
Where it fits on the car
This lock nut fits within the gearbox / transmission pinion shaft assembly. It forms part of the internal transmission retaining hardware.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99903403300
The product you are viewing cross references to these numbers
- 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 Boxster 987 MKII 2.9L 2009-12
- Porsche Boxster S 987 MKII 3.4L 2009-12
- Porsche Boxster 981 2.7L 2012-16
- Porsche Boxster 981 S / GTS 3.4L 2012-16
- Porsche Boxster 718 2.0L Manual (300 Bhp) 2017>>
- Porsche Boxster 718 2.0L PDK (300 Bhp) 2017>>
- Porsche Boxster S 718 2.5L Manual (350 Bhp) 05/2017>>
- Porsche Boxster S 718 2.5L PDK (350 Bhp) 05/2017>>
- Porsche Boxster T 718 2.0L Manual (300 Bhp) 01/2019>>
- Porsche Boxster T 718 2.0L PDK (300 Bhp) 01/2019>>
- Porsche Boxster GTS 718 2.5L Manual (365 Bhp) 05/2017>>
- Porsche Boxster GTS 718 2.5L PDK (365 Bhp) 05/2017>>
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
- Porsche Cayman 2.9L 987C MKII 2009-12
- Porsche Cayman S / R 3.4L 987C MKII 2009-12
- Porsche Cayman 2.7L 981 2013-16
- Porsche Cayman S / GTS 3.4L 981 2013-16
- Porsche Cayman GT4 3.8L 2015-16
- Porsche Cayman 718 2.0L Manual (300 Bhp)
- Porsche Cayman 718 2.0L PDK (300 Bhp)
- Porsche Cayman S 718 2.5L Manual (350 Bhp)
- Porsche Cayman S 718 2.5L PDK (350 Bhp)
- Porsche Cayman T 718 2.0L Manual (300 Bhp)
- Porsche Cayman T 718 2.0L PDK (300 Bhp)
- Porsche Cayman GTS 718 2.5L Manual (365 Bhp)
- Porsche Cayman GTS 718 2.5L PDK (365 Bhp)
- Porsche 924 2.0L 1976-79
- Porsche 924 2.0L 1980-85
- Porsche 924 Turbo 2.0L 1979-81
- Porsche 924 Turbo 2.0L 1982-84
- Porsche 924 Carrera GT 2.0L 1981
- Porsche 924 Carrera GTS 2.0L 1982
- Porsche 924S 2.5L 1986-87
- Porsche 924S 2.5L 1988
- Porsche 944 2.5L 8V 1982-87
- Porsche 944 2.7L 8V 1988-89
- Porsche 944S 2.5L 16V 1987-88
- Porsche 944S2 3.0L 16V 1989-91
- Porsche 944 Turbo 2.5L 8V 1985-88
- Porsche 944 Turbo 2.5L 8V 1989-91
- Porsche 944 Turbo S 2.5L 8V 1988
Fits:
For cars with manual transmission
Porsche 924 1976-88
Porsche 944 1982-91
Porsche 986 / 987 / 981 / 982 Boxster 1997>>
Porsche 987 / 981 / 982 Cayman 2005>>
Click 'Zoom in' for large parts diagram.
Diagram ref no 4
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
016409399B
The product you are viewing cross references to these numbers
- 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
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
- 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
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
- 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 Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
- Porsche 968 3.0L 1992-94
- Porsche 968 Sport 3.0L 1994-95
- Porsche 968 CS 3.0L 1993-95
- Porsche 968 Turbo S 3.0L 1993-94
The Front Oil Pump Seal for Tiptronic Gearbox is a OE MATCH transmission sealing component designed to prevent automatic transmission fluid (ATF) from leaking around the front oil pump assembly. This seal maintains proper fluid containment within the gearbox, ensuring correct hydraulic pressure and reliable transmission operation.
Fits:
- 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 Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
- Porsche 968 3.0L 1992-94
- Porsche 968 Sport 3.0L 1994-95
- Porsche 968 CS 3.0L 1993-95
- Porsche 968 Turbo S 3.0L 1993-94
Diagram Ref No 2
What This Product Does:
- Sealing the front oil pump assembly
- Preventing transmission fluid leaks
- Maintaining proper hydraulic pressure inside the gearbox
- Protecting internal transmission components
- Ensuring consistent automatic gear shifting
Symptoms Of Wear Or Failure:
- Transmission fluid leaks at the front of the gearbox
- ATF residue under the vehicle
- Low transmission fluid levels
- Slipping or delayed gear engagement
- Unusual transmission noise
- Transmission overheating
Why Replacement Matters:
- Prevent transmission fluid leaks
- Maintain proper hydraulic pressure
- Ensure smooth and reliable gear changes
- Protect internal transmission components
- Avoid costly gearbox repairs or failure
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99639701000
The product you are viewing cross references to these numbers
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