Gearbox Mounts

Our polyurethane bushes are ideal replacements for worn or damaged parts. Engine mount bushes are particularly prone to cracking of the rubber because of a large amount of voiding in the material to allow for excessive movement. For an insert only please use PFR57-521.
OEM Part Number: 98737502305
OEM Part Number: 9A137502322
Fits:
Porsche Boxster 986 (1997-2004)
Porsche Boxster 987 (2005-2009)
Porsche Cayman 987C (2005 - 2009)
up to 2009 with engine codes M9625, M9626, M9720, M9721 & M9722
DIAGRAM REFERENCE: 20
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
PFR57-520
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 Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08

SET OF 2
AVAILABLE FOR
Porsche 986 Boxster and 987 Boxster / 987 Cayman
FITS MODEL VARIANTS INCLUDING MK.1 & MK.2 with 6 Speed Manual or PDK Transmission.
• The RSS Tarmac Series Performance Transmission Mounts are designed for the Porsche driver who demands the absolute maximum in precision handling, feedback and control from their chassis.
• With factory Transmission mounts, the drivetrain will move independent of the chassis during acceleration, deceleration and cornering loads. This movement can upset the balance of the vehicle and create negative handling effects.
• RSS Performance Transmission mounts minimize these effects by utilizing specialized polyurethane bushings which offer a firmer, more direct driving feel with optimum feedback.
• This upgrade will NOT significantly affect ride quality or cause knock sensor issues commonly associated with solid transmission mounts.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
627
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 2009-2012
- Porsche Boxster S 987 MKII 3.4L 2009-2012
- 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 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.