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Gasket Sets / Gaskets / Seals / Lock Nuts
Fits:
Porsche 915 Gearbox 5 Speed
Manual transmission
- 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

Fits:
Porsche 911 - 1970 to 1983
For Sportomatic only
Click 'Zoom in' for large parts diagram.
Diagram ref no 17
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
925301191
The product you are viewing cross references to these numbers
- 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

Fits:
Porsche 911 Carrera 1972-86
Transmission TYPE 915
Click 'Zoom in' for large parts diagram.
Diagram ref no 23
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91530119100
The product you are viewing cross references to these numbers
- 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
Fits:
Porsche 911 Carrera 1972-86
Transmission TYPE 915
Diagram ref no 23
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91530119100
The product you are viewing cross references to these numbers
- 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
Set of gaskets & seals for gearbox overhaul.

Fits:
Porsche 911 1972-86 Cars with 915 Gearbox
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91530091101
The product you are viewing cross references to these numbers
- 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
Set of gaskets & seals for gearbox overhaul.

Fits:
Porsche 911 1972-86 Cars with 915 Gearbox
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91530091101
The product you are viewing cross references to these numbers
- 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

Fits
Porsche 911 1972-86
Porsche 911 (930) Turbo 1975-89
Click 'Zoom in' for large parts diagram.
Diagram ref no 9
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91530322500
The product you are viewing cross references to these numbers
- 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 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
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
- 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 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

Fits:
Porsche 911 1972-86
Manual transmission
Click 'Zoom in' for large parts diagram.
Diagram ref no 51
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91530228200
The product you are viewing cross references to these numbers
- 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
Fits:
Porsche 911 1972-86
Manual transmission
Diagram ref no 51
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91530228200
The product you are viewing cross references to these numbers
- 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

Fits:
Porsche 911 1972-73 (TYP 915) upto:
G >> 733 7374
G >> 723 0507
G >> 783 0830
Porsche 911 Carrera 1974-86
Click 'Zoom in' for large parts diagram.
Diagram ref no 13
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911318241
The product you are viewing cross references to these numbers
- 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

Fits:
Porsche 911 1972-73 (TYP 915) upto:
G >> 733 7374
G >> 723 0507
G >> 783 0830
Porsche 911 Carrera 1974-86
Click 'Zoom in' for large parts diagram.
Diagram ref no 13
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911318241
The product you are viewing cross references to these numbers
- 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

Fits:
Porsche 911 1972-73 (TYP 915) from:
G 733 7575 >>
G 723 0507 >>
G 783 0838 >>
Porsche 911 Carrera 1973-86
Click 'Zoom in' for large parts diagram.
Diagram ref no 13
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911332740
The product you are viewing cross references to these numbers
- 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
A rubber shaft oil seal (radial seal) for the main/input shaft of a 901/915-series gearbox. It fits around the rotating shaft and seals the interface between the rotating shaft and the gearbox housing to prevent gearbox oil leaks.
Dimensions: 23 mm (shaft diameter) × 35 mm (outer diameter) × 8/11 mm thickness (seal housing/dual-lip design).
Fits:
Porsche 911 1972 - 1973 (TYP 915) from:
G 733 7575 >>
G 723 0507 >>
G 783 0838 >>
Porsche 911 Carrera 1973 - 1986
Diagram ref no 11
This seal prevents gearbox oil from escaping around the input or main shaft, ensuring the transmission remains properly lubricated. It also blocks dirt, water, and other contaminants from entering the gearbox, helping preserve internal components and maintain correct operating pressure. By replacing a worn, hardened, or cracked original seal, it restores a clean, leak-tight barrier for reliable long-term gearbox performance.
Original gearbox seals degrade over time: rubber lips harden or crack, springs lose tension, and sealing surfaces wear. A failing main-shaft seal typically leads to:
• Gearbox oil leaks
• Loss of gearbox oil over time (low oil level)
• Contamination ingress (dirt, water), leading to accelerated gearbox wear or internal damage
• Messy drip underneath the car and gearbox housing
Replacing the seal with a correct-spec new unit restores proper sealing, preserves gearbox oil integrity, and helps prevent costly internal damage or gearbox failure.
You should replace this seal if:
• Gearbox oil leaks are visible around the input shaft or bellhousing area
• There is seepage, oil dripping, or a film of oil on the underside of gearbox or clutch area
• The old seal appears cracked, hardened, or visibly damaged
• You are doing a gearbox rebuild, overhaul or maintenance
• You notice loss of gearbox oil or suspect contamination ingress
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911332740
The product you are viewing cross references to these numbers
- 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

Fits:
Porsche 911 2.0ltr - 3.2ltr 1963 to 1986
Porsche 930 3.0L - 3.3L 1975-89
Porsche 912 1.6ltr 1966 to 1976
Click 'Zoom in' for large parts diagram.
Diagram ref no 8
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911318540
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- 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 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 912E 4CYL 1976
-
replacement transmission, transmission case 1978-83 302-00
-
gear housing, transmission cover 1978-83 302-05
-
gears and shafts 5. speed transmission - G 915 - 911 1978-83 303-15
-
shift rods, shift forks 5. speed transmission - G 915 / G 930 - 911 1978-83 304-00
-
replacement transmission, transmission case SPM - G 925/16 - 911 1978-83 308-00
Porsche Gearbox & Transmission Gasket Sets, Gaskets, Seals & Lock Nuts | Precision Sealing for Drivetrain Integrity
Gaskets, seals, and lock nuts are essential components that protect your Porsche’s gearbox or transmission system from fluid leaks, contamination, and vibration. These parts maintain internal pressure, ensure proper lubrication, and secure vital fasteners under extreme temperature and torque conditions — all of which are crucial for reliable, long-term gearbox performance.
At Design911, we supply premium gearbox gasket sets, individual seals, and locking hardware engineered to match or exceed original performance specifications. Manufactured from advanced composite, rubber, and metal-reinforced materials, our gasket kits ensure a perfect fit and dependable sealing across all Porsche models.
Whether you’re performing a gearbox rebuild, addressing a transmission leak, or refreshing driveline components, our gaskets, seals, and lock nuts deliver precision, reliability, and protection against future wear or oil loss.
What Do Gearbox Gaskets, Seals & Lock Nuts Do?
Each component plays a vital role in maintaining your Porsche’s gearbox integrity and smooth power delivery.
Core Functions:
Together, they preserve internal oil pressure, reduce wear
on moving parts, and ensure consistent transmission performance in both road
and track conditions.
Why Do Gearbox Gaskets, Seals
& Lock Nuts Fail or Wear Out?
Over time, these components endure significant thermal cycling, pressure changes, and exposure to fluids. Age and wear lead to material degradation and potential leaks.
Common Causes of Failure Include:
- Gasket shrinkage, cracking, or compression fatigue.
- Seal hardening from heat or exposure to aggressive fluids.
- Damaged or corroded sealing surfaces during service.
- Lock nuts loosening due to vibration or over-torqueing.
- Improper installation or reusing old sealing materials.
Failure of any of these parts can result in oil leaks, gearbox noise, or internal component damage — all of which compromise drivetrain performance and reliability.
Why Replace Your Porsche Gearbox Gaskets, Seals & Lock Nuts?
Replacing worn or leaking gaskets and seals prevents oil loss and transmission failure, while fresh locking hardware ensures secure, vibration-proof assembly. During any gearbox or differential service, new gaskets and seals should always be installed to guarantee long-term reliability.
Key Benefits:
- Prevents oil leaks and contamination of internal components.
- Maintains gearbox pressure and correct lubrication levels.
- Reduces noise, vibration, and harshness (NVH).
- Protects against long-term wear and gear damage.
- Precision fitment for Porsche manual, automatic, and PDK systems.
- Ideal for gearbox rebuilds, maintenance, and performance upgrades.
Replacing these parts as a complete kit ensures every sealing point and fastener is restored to optimal condition — protecting your investment and performance.
Highlights
- Complete Porsche gearbox gasket sets, seals, and lock nut kits.
- Manufactured from high-quality materials for strength and longevity.
- Designed for perfect fitment and superior oil retention.
- Resistant to heat, pressure, and transmission fluid degradation.
- Suitable for Porsche 911, Cayman, Boxster, Panamera, and more.
- Essential for gearbox servicing, rebuilds, and leak prevention.