Whiteline Gearbox Positive Shift Kit – 2008-2021 Subaru WRX / STI / 2005-2013 Legacy GT

Eliminate Drivetrain Slop, Sharpen Shift Feel
The Whiteline Gearbox Positive Shift Kit reduces movement in the transmission and differential mount bushings by filling the void space around the OEM rubber with polyurethane inserts. Transmission movement under acceleration and load changes allows the drivetrain to shift position slightly, which is felt as vagueness in shift quality and inconsistency in throttle response. These inserts tighten up that compliance without requiring full bushing replacement.

DETAILS

• Polyurethane insert kit for transmission and differential mount positions
• Reduces drivetrain movement under acceleration and load changes
• Improves shift quality precision and throttle response consistency
• No removal of OEM bushings required — inserts fill the void
• Fits 2008-2021 Subaru WRX, STI, and 2005-2013 Legacy GT

How Drivetrain Mount Compliance Affects Shift Feel
When the transmission can move under load, the shift lever connection to the transmission moves with it. The physical distance between your hand and the shift forks changes slightly as the drivetrain loads up and unloads. This shows up as inconsistency in shift throw feel and a vague quality to gearchanges that can’t be fixed by adjusting the shift linkage. Reducing transmission movement addresses the root cause.

Insert Design — Effective Without Full Replacement
Whiteline’s insert kit works with the OEM mount hardware. The inserts are sized to fill the void space in the factory mount, reducing compliance in all directions without completely eliminating it. This preserves some NVH absorption while significantly reducing unwanted movement. Installation is substantially simpler than pressing out and replacing the OEM bushings.

GR/VA WRX and STI — High-Demand Drivetrain Applications
The EJ and FA engines in the 2008-2021 WRX and STI produce significant torque impulses under hard acceleration. The OEM drivetrain mounts are adequate at moderate loads but allow noticeable movement under performance driving conditions. The Positive Shift Kit tightens this up without introducing the harshness of fully solid mounts.

Why Choose Whiteline

Whiteline has been engineering suspension components from their facility in Australia since 1979. Every product in their catalog is developed with a clear goal: measurable improvement in handling, stability, and tyre contact. Whiteline’s polyurethane bushings, sway bars, control arms, and alignment correction kits are engineered using finite element analysis and validated on track before they reach the market. Their components are direct-fit, bolt-on solutions designed for enthusiasts who want real performance gains without fabrication or custom work.

The RallySport Take

One of the most satisfying interior feel upgrades for any WRX or STI. Shift quality improvement is immediate and noticeable — the transmission feels more direct and planted after installation. A high-impact upgrade for a low cost.

What’s in the Box

• Polyurethane insert kit for transmission and differential mount positions
• Reduces drivetrain movement under acceleration and load changes
• Improves shift quality precision and throttle response consistency
• No removal of OEM bushings required — inserts fill the void

Fitment