GrimmSpeed Street Transmission Mount

GrimmSpeed Performance Transmission Mount | Subaru AWD Manual Models

Lock Down Your Drivetrain for More Predictable Shifting!

Factory transmission mounts prioritize comfort and cost, leaving significant room for performance improvement. The GrimmSpeed Transmission Mount dramatically reduces unwanted drivetrain movement, delivering sharper shifting and greater confidence under acceleration, cornering, and spirited driving.

The key lies in the 75A durometer polyurethane bushings — engineered to minimise transmission flex under high torque loads without introducing excessive noise or harshness into the cabin.

This mount is a direct OEM-fit solution for most AWD Subaru manual transmission platforms. Since 5-speed and 6-speed cases differ slightly, the kit includes a 5-Speed Adapter Spacer for perfect alignment when needed.

Installation is simple and reliable thanks to a factory-style press-fit stud design on the stainless-steel bracket — preventing misalignment and ensuring a hassle-free mounting process. The kit arrives fully assembled with all required hardware included.

Performance Upgrade vs OEM

Subaru offers different stiffness levels from factory:

• Softest: WRX OEM Mount
• Mid-Level: STI OEM Mount
• Firmest: Group N Mount

The GrimmSpeed Transmission Mount uses 75A bushings, providing:

• 2x stiffer than Group N
• 5x stiffer than OEM STI mount
• 16x stiffer than OEM WRX mount

This means dramatically improved drivetrain control and a more connected shifting experience — while remaining daily-friendly. NVH increases are minimal during normal driving.

Fitment

• 2004–2021 Subaru STI (6MT)
• 2002–2014 Subaru WRX (5MT)*
• 2015–2024 Subaru WRX (6MT)*
• 2004–2008 Subaru Forester XT (5MT)*
• 2005–2009 Subaru Legacy GT (5MT/6MT)*
• 2005–2009 Subaru Outback XT (5MT)*
• 1993–2022 Subaru Impreza (5MT)*

*Not compatible with 4EAT, 5EAT, CVT, or RWD transmissions

Not compatible with RWD Aisin AZ6 transmission found in BRZ / FRS / GR86.

Included

• GrimmSpeed Transmission Mount (pre-assembled)
• 5-Speed Adapter Spacer
• All required mounting hardware

Quick Specs

• 6061 Billet Aluminum & 304 Stainless Steel construction
• Red 75A durometer bushings for a solid shift feel
• Compatible with Subaru 5MT and 6MT AWD manual transmissions
• Includes adapter spacer for 5-speed fitment
• Direct fit – no modification required