Gearbox Mounts
Gearbox mount hexagon-head bolt nut (part number 90007606402), designed for Porsche 911, 912, and 930 models (1965–1989). Manufactured to match original Porsche specifications, this M8 nut provides precise thread engagement, corrosion resistance, and dependable fastening strength for gearbox mounting applications.
Sold each.
Fits:
Porsche 911/912 1965 - 1989
Porsche 911 (930) Turbo 1975 - 1989
Diagram Ref No 9
Ideal for gearbox mount installations, transmission rebuilds, or hardware restorations on classic air-cooled Porsche models.
Over time, gearbox mounting hardware can corrode or lose torque retention due to heat, vibration, and age. A fresh nut ensures secure fastening and proper alignment of gearbox mounts. Replace during gearbox removal, rebuild, or mount replacement to maintain reliability and prevent drivetrain movement or noise.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90007606402
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 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
Fits:
Porsche 911/912 1965-89
Porsche 911 (930) Turbo 1975-89
Diagram Ref No 7
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90007503203
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 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
Enhance drivetrain precision and performance with the HD Semi-Solid Engine / Transmission Mount Set, designed specifically for Porsche 911 and 912 models
These heavy-duty mounts replace the factory rubber units with a semi-solid, high-durometer compound — around 25 % firmer than standard — providing improved control and response without sacrificing comfort.
The semi-solid design effectively reduces engine and gearbox movement under acceleration, braking, and cornering, giving sharper throttle response, smoother gear changes, and tighter handling stability.
One kit includes 2 halves of mount, (2 kits required per car).
Fits:
Work as engine mounts in 1965-1989 911/912/930
Work as transmission mounts in 1972-1986 911/912/930 (915/930 Transmission Only)
What This Product Does:
- In the Heavy Dusty semi-solid version, the stiffer rubber reduces unwanted flex while still providing some damping, hence a compromise between fully soft and fully rigid (solid) mounts.
Symptoms / Indications That Replacement Or Upgrading Is Needed:
- Engine / gearbox movement or “rocking” under throttle or deceleration
- Clunking or banging noises from the engine bay when shifting or applying torque
- Increased vibration in the cabin or floorboard
- Misalignment over time, causing stress or wear in driveshafts, couplings, or mount brackets
- Feel of looseness or lag in throttle response or drivetrain “lash”
Why Upgrading to HD Semi-Solid Mounts Matters:
- Sharper Response & Less Flex - Because mounts deflect less, the engine / gearbox stays more stable under load, improving throttle response, shift feel, and power delivery.
- Better Drivetrain Alignment - Less movement helps maintain correct angle relationships between engine, gearbox, driveshafts, etc., reducing stress and wear.
- Improved Stability Under Load - During hard cornering, braking, or acceleration, stiffer mounts help avoid drivetrain “twist” or slop, which can upset handling balance.
- Dampening Retained - Semi-solid design still absorbs vibration and noise more than fully rigid mounts, providing a balanced tradeoff for street use.
- Straightforward Installation - Because the inserts fit existing mount shells, installation is simpler — no need for custom brackets or drastic modifications.
- Good for Performance / Restoration Builds - Especially in cars that see spirited driving or occasional track use, the HD semi-solid mounts are a common upgrade that improves control without completely sacrificing comfort.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91137504306
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 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
One kit includes 2 halves of mount, (2 kits required per car).
Fits:
Work as engine mounts in 1965-1989 911/912/930
Work as transmission mounts in 1972-1986 911/912/930 (915/930 Transmission Only)
Fits to number 8 on the diagram.
High Density engine/transmission mounts are the perfect compromise between stock rubber and our Semi-Solid mounts. Their heavy duty 25% higher durometer rubber construction makes them ideal for performance oriented cars, but still allows absorption of vibrations and noise associated with solid mounts. Installs in stock motor mount or transmission mount hangers replacing worn out factory rubber.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91137504306
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 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)

Fits:
Porsche 911 - 1978 to 1989
Porsche 964 - 1989 to 1994
Porsche 993 - 1994 to 1998
Click 'Zoom in' for large parts diagram.
Diagram ref no 12
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90016901401
The product you are viewing cross references to these numbers
- 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)
- 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
Fits:
Porsche 911 2.7L to 3.2L & 930 3.3L
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
504-9502
The product you are viewing cross references to these numbers
- 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)

Fits:
Porsche 911 1969-89
Porsche 930 Turbo 1975-89
Click 'Zoom in' for large parts diagram.
Diagram ref no 5
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93037531701
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 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
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camshaft housing chain case 911 1978-83 103-05
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valve control left 911 1978-83 103-10
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valve control right 911 1978-83 103-15
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engine lubrication oil pump 911 1978-83 104-00
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air cleaner 911 TURBO 1978-83 106-05
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SPM - vacuum system for clutch release 911 1978-83 106-10
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k-jetronic I 911 TURBO 930.60/61, 930.62/66 1978-83 107-20
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k-jetronic II 911 TURBO 1978-83 107-30
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k-jetronic III 911 TURBO 1978-83 107-35
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charge air cooler 911 TURBO 1978-83 107-45
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air injection 911 TURBO 1978-83 108-05
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engine suspension 911 1978-83 109-00
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replacement transmission, transmission case 1978-83 302-00
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gear housing, transmission cover 1978-83 302-05
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gears and shafts 4. speed transmission - G 930/34 - 911 1978-83 303-05
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shift rods, shift forks 5. speed transmission - G 915 / G 930 - 911 1978-83 304-00
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transmission suspension 911 1978-83 306-00
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clutch release SPM - G 925/16 - 911 1978-83 307-00
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replacement transmission, transmission case SPM - G 925/16 - 911 1978-83 308-00
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steering accessories lower 911 1978-83 403-00
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steering accessories upper 911 1978-83 403-05
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disc brake front axle 911 TURBO 1978-83 602-05
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brake fluid reservoir, brake master cylinder 911 1978-83 604-00
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transmission control 911 1978-83 701-00
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pedals accelerator control 911 1978-83 702-10
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YORK compressor mounting and driving mechanism 911 1978-83 813-30
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NIPPONDENSO compressor mounting and driving mechanism 911 TURBO 1978-83 813-35
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engine electrics steering lock 911 1978-83 901-00
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battery, fuse box 911 1978-83 902-00
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windscreen wiper system 911 1978-83 904-00
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rear window wiper 911 1978-83 904-05
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cruise control 911 1978-83 907-00
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camshaft housing chain case 911 1987-89 103-05
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valve control left 911 1987-89 103-10
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valve control right 911 1987-89 103-15
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engine lubrication oil pump lines 911 1987-89 104-00
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air cleaner 911 TURBO 930.66/68 1987-89 106-05
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throttle linkage bracket 911 1987-89 107-12
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K-JETRONIC I 911 TURBO 930.66/68 1987-89 107-20
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K-JETRONIC II 911 TURBO 930.66/68 1987-89 107-30
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K-JETRONIC III 911 TURBO 930.66/68 1987-89 107-35
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charge air cooler 911 TURBO 930.66/68 1987-89 107-45
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air injection 911 TURBO 930.66/68 1987-89 108-05
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engine suspension 911 1987-89 109-00
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clutch release hydraulic 911 1987-89 301-07
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replacement transmission transmission case 911 1987-89 302-00
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replacement transmission transmission case 911 1987-89 302-02
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gear housing transmission cover 911 1987-89 302-05
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steering parts lower 911 1987-89 403-00
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gear housing / transmission cover 911 1987-89 302-07
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steering parts upper 911 1987-89 403-05
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gears and shafts 4-speed gear wheel sets see group 3/03/00 303-05
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shift rods shift forks for 4-speed and 5-speed 911 1987-89 304-00
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tensioning plate shift control lock device 5-speed 911 1987-89 304-05
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transmission suspension 911 1987-89 306-00
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brake front axle 911 TURBO / CARRERA M491 1987-89 602-05
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transmission control 911 TURBO 1987-88 701-00
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transmission control 911 CARRERA / TURBO 1987-89 701-01
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pedals for RIGHT HAND DRIVE 911 CARRERA 19787-89 / TURBO 1989- 702-07
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clutch actuation, clutch master cylinder, clutch pipeline 911 CARRERA 1978-89 / TURBO 1989- 702-08
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window glazing 911 SPEEDSTER 1987-89 805-10
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Camshaft housing chain case 911 1984-86 103-05
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Valve control left 911 1984-86 103-10
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valve control right 911 1984-86 103-15
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Engine lubrication oil pump lines 911 1984-86 104-00
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Air cleaner 911 TURBO 930.66/68 1984-86 106-05
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Throttle linkage bracket 911 1984-86 107-12
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K-JETRONIC I 911 TURBO 930.66/68 1984-86 107-20
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K-JETRONIC II 911 TURBO 930.66/68 1984-86 107-30
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K-JETRONIC III 911 TURBO 930.66/68 1984-86 107-35
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Charge air cooler 911 1984-86 107-45
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Air injection 911 TURBO 930.66/68 1984-86 108-05
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Engine suspension 911 1984-86 109-00
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shift rods shift forks SPM - G 925/16 - 911 1978-83 310-00
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transmission suspension SPM - G 925/16 - 911 1978-83 312-00
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compressor mounting driving mechanism 911 1987-89 813-20
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condenser lines accessories and others REAR 911 1987-89 813-55
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engine electrics - 1 - 911 TURBO 1987-89 901-00
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battery, starter, generator 911 1987-89 902-05
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horn 911 1987-89 903-00
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windscreen wiper system 911 1987-89 904-00
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rear window wiper 911 1987-89 904-05
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cruise control 911 1987 907-00
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special model flatnose design pop-up headlight 911 TURBO M506 1988-89 980-00
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replacement transmission, transmission case 911 1984-86 302-00
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gear housing, transmission cover 911 1984-86 302-05
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gears and shafts 5-speed 911 1984-86 303-15
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shift rods shift forks for 4-speed and 5-speed 911 1984-86 304-00
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transmission suspension 911 1984-86 306-00
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steering parts lower 911 1984-86 403-00
-
steering parts upper 911 1984-86 403-05
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Brake front axle 911 TURBO / CARRERA M491 1984-86 602-05
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transmission control 911 1984-86 701-00
-
pedals accelerator control 911 1984-86 702-10
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pedals for accelerator control 911 1987-89 702-10
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Compressor mounting and driving mechanism 911 1984-86 813-20
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cruise control 911 1984-86 907-00
-
engine electrics - 1 - 911 TURBO 1984-86 901-00
-
battery, starter, generator 911 1984-86 902-05
-
windscreen wiper system 911 1984-86 904-00
-
rear window wiper 911 1984-86 904-05
Porsche Gearbox Mounts | Stability, Precision & Reduced Drivetrain Vibration
Gearbox mounts (also known as transmission mounts) are essential components that secure your Porsche’s gearbox to the chassis while isolating vibration and absorbing torque movement. These mounts play a crucial role in maintaining drivetrain alignment, smooth shifting, and overall driving comfort.
At Design911, we supply high-quality gearbox mounts and transmission mounting kits engineered to meet or exceed original performance specifications. Constructed from advanced rubber, polyurethane, or hydraulic materials, each mount provides the perfect balance of flexibility and strength — ensuring your Porsche maintains stable, refined performance under both road and track conditions.
Whether you’re restoring a classic Porsche or maintaining a modern performance model, our gearbox mounts deliver long-lasting stability, improved handling, and reduced drivetrain noise and harshness.
What Do Gearbox Mounts Do?
Gearbox mounts act as the vital connection between your Porsche’s transmission system and chassis, absorbing torque and vibration while maintaining alignment under load.
Core Functions:
- Secure the gearbox in place under acceleration, braking, and cornering.
- Absorb vibration and noise from the drivetrain.
- Maintain correct driveshaft and linkage alignment.
- Prevent excess movement that can stress surrounding components.
Without properly functioning gearbox mounts, excessive drivetrain movement can lead to harsh shifting, vibration, and even damage to exhaust, linkage, or driveshaft components.
Why Do Gearbox Mounts Fail or Wear Out?
Over time, gearbox mounts degrade due to exposure to engine heat, torque stress, and environmental factors such as oil contamination or moisture.
Common Causes of Failure Include:
- Rubber deterioration or cracking from heat and age.
- Hydraulic fluid leakage in fluid-filled mounts.
- Metal fatigue in high-performance or heavy-load use.
- Oil contamination softening rubber compounds.
- Continuous torque stress from aggressive acceleration.
As mounts weaken, you may experience clunking noises, drivetrain vibration, gear lever movement, or difficulty shifting — all signs that your gearbox mounts need replacement.
Why Replace or Upgrade Your Gearbox Mounts?
Replacing worn gearbox mounts restores drivetrain stability, smoother shifting, and reduced vibration. Upgrading to reinforced or performance mounts enhances control and torque response, especially on tuned or track-driven Porsches.
Key Benefits:
- Restores smooth, vibration-free gear changes.
- Prevents drivetrain movement and component stress.
- Improves handling precision and throttle response.
- Reduces noise, vibration, and harshness (NVH).
- Available in rubber, polyurethane, and performance-spec designs.
- Ideal for maintenance, upgrades, or complete gearbox servicing.
Replacing mounts in pairs ensures balanced performance and consistent driveline alignment.
Highlights
- Premium Porsche gearbox and transmission mounts.
- Engineered for strength, durability, and vibration reduction.
- Direct-fit replacements for Porsche 911, Cayman, Boxster, and others.
- Reinforced designs for performance or track applications.
- Reduces stress on transmission and drivetrain components.
- Essential for smooth shifting, refinement, and drivetrain longevity.