do not press the back button…
Enter your VAT number here and click Verify:
Your details have been verified. VAT number registered to:
,
.
Your order will now be zero rated for VAT purposes. We reserve the right to verify these details after your order request has been made and reinstate VAT if required.
Your VAT details were not recognised or were invalid. Your VAT number must be matched to your Billing Country as specified above. This is currently specified as . You do not need to enter the country code part of your VAT number as this has already been selected in your billing address details above.
The VAT number checking service is currently offline. Please supply your VAT details within the comments or special instructions field below and we will apply a VAT discount after placing your order request.
Gearbox Casing / Casing Parts
Gear Selector Shaft Oil Seal
OE Match gear selector shaft oil seal for
classic Porsche 911 and 912 manual gearboxes. Designed to replace a worn or
leaking original seal, this component helps prevent transmission oil from
escaping around the gear selector shaft where it passes through the gearbox
housing.
Fits:
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
Diagram ref no 8
The seal provides a barrier between the moving selector shaft and gearbox casing, helping retain the correct transmission oil level and protecting the surrounding components from oil contamination.
What Does the Gear Selector Shaft Oil Seal Do?
The gear selector shaft transfers movement from the gear lever linkage into the gearbox, allowing the driver to select different gears.
The oil seal fits around this shaft and prevents gearbox oil from escaping while allowing the shaft to move during gear changes. A properly functioning seal helps maintain the transmission oil level and keeps the gearbox exterior clean and dry.
Why Does It Fail?
Over time, the sealing material can harden, shrink or lose flexibility due to age, heat and prolonged contact with transmission oil.
Common causes of failure include:
- Age-related deterioration of the sealing lip
- Hardened or cracked rubber
- Wear from repeated selector shaft movement
- Corrosion or damage to the shaft sealing surface
- Incorrect installation or previous gearbox repairs
- Excessive shaft movement or wear
As the seal deteriorates, transmission oil may begin to seep around the selector shaft.
When Should It Be Replaced?
A replacement may be required if you notice:
- Gearbox oil leaking around the selector shaft
- Oil collecting on the underside of the transmission
- Drips beneath the gearbox
- A persistent oily residue around the selector linkage
- A damaged or hardened seal during gearbox servicing
The seal should also be inspected whenever the gearbox selector mechanism is dismantled or the transmission is removed for restoration.
Checks During Replacement
Before fitting a new oil seal, inspect the selector shaft for corrosion, scoring or excessive movement. Check the gearbox breather and surrounding seals to ensure the leak has been correctly identified.
The new seal should be installed squarely and to the correct depth, without damaging the sealing lip or shaft surface.
Porsche 911 / 912 Gearbox Oil Seals & Transmission Components
Gearbox oil seals are essential for maintaining the correct lubrication of classic Porsche manual transmissions. The gear selector shaft oil seal prevents transmission oil from leaking where the selector shaft enters the gearbox housing.
On older Porsche 911 and 912 models, ageing seals can become brittle or worn, allowing gearbox oil to escape. Replacing a leaking seal helps protect the transmission against lubricant loss and prevents oil contamination around the gear linkage and gearbox casing.
OE Match seal is a 15 × 24 × 7 mm replacement selector shaft oil seal for selected Porsche 911, 912 and 930 Turbo manual gearboxes. It is particularly suitable for maintenance and restoration of classic Porsche transmissions.
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
Shop Securely
12 Month Warranty
Worldwide Delivery
Porsche Gearbox Casings & Casing Parts | Strength, Precision & Thermal Stability for Reliable Transmission Performance
The gearbox casing is the structural foundation of your Porsche’s transmission system. It houses and supports all internal components — including gears, bearings, shafts, and seals — ensuring correct alignment, strength, and efficient operation. High-quality casing components are essential for maintaining gearbox integrity, preventing leaks, and reducing vibration or mechanical stress.
At Design911, we supply precision-engineered gearbox casings and casing components designed to meet or exceed original performance specifications. Manufactured from high-strength aluminium or magnesium alloys, each casing ensures excellent rigidity, heat dissipation, and dimensional accuracy.
Whether you’re rebuilding a classic 911 transmission, repairing a damaged casing, or upgrading for performance reliability, our range of Porsche gearbox casings and casing parts guarantees strength, fitment precision, and long-term durability.
What Do Gearbox Casings & Casing Parts Do?
The gearbox casing acts as a rigid housing that protects internal components from damage, contamination, and misalignment while maintaining lubrication and temperature control.
Core Functions:
- Provides structural support and alignment for all internal gearbox components.
- Protects gears, shafts, and bearings from debris and external damage.
- Maintains correct oil levels and internal pressure.
- Ensures efficient heat dissipation for optimal transmission operation.
- Prevents leaks through integrated seals and machined joints.
Without a properly functioning casing, gearbox alignment and performance can degrade — leading to premature wear, oil leaks, and even transmission failure.
Why Do Gearbox Casings & Components Fail or Get Damaged?
Gearbox casings are exposed to mechanical stress, vibration, and heat over time, which can cause fatigue, cracking, or oil leaks.
Common Causes of Failure Include:
- Cracks or fractures from impact or over-torqued bolts.
- Corrosion or oxidation, particularly on older magnesium casings.
- Warping due to overheating or poor heat dissipation.
- Damaged or worn sealing surfaces causing oil leaks.
- Incorrect assembly or misalignment during installation.
When the casing or its mating surfaces fail, it can cause oil leakage, misaligned gears, excessive noise, or internal component wear — compromising gearbox performance and reliability.
Why Replace Your Porsche Gearbox Casing or Casing Parts?
Replacing a damaged or worn gearbox casing ensures structural integrity, correct alignment, and proper sealing — vital for transmission efficiency and performance. Upgraded or remanufactured casings also enhance durability and thermal control in high-performance applications.
Key Benefits:
- Restores proper gearbox alignment and internal balance.
- Prevents oil leaks and contamination of internal components.
- Improves heat management and mechanical strength.
- Reduces vibration and driveline noise.
- Ensures long-term reliability during rebuilds or performance upgrades.
- Available for manual, automatic, and PDK Porsche transmissions.
A high-quality gearbox casing or replacement part is essential during transmission rebuilds to maintain correct tolerances and optimal drivetrain function.
Highlights
- Precision Porsche gearbox casings and casing parts.
- Manufactured from high-strength aluminium or magnesium alloys.
- Perfect fitment for Porsche 911, Cayman, Boxster, and classic models.
- Designed for strength, rigidity, and long-term reliability.
- Restores transmission efficiency and structural integrity.
- Ideal for rebuilds, repairs, or performance transmission upgrades.
Monday-Friday: 8.30am - 5.30pm (GMT)
Saturday: Closed
Sunday: Closed