Top 5 Shifter Mods For Your Subaru

If your shift knob wiggles in gear or finding a gate feels vague, the problem is usually spread across several parts in the linkage, not one. Every bushing and joint between your hand and the transmission adds a little play, and after 100,000+ miles of road salt, heat, and gear changes, that play adds up at the knob.

These five upgrades address the linkage from the pivot point up through the shifter itself. Each one can be done on its own, but they work best together, and can be easier to install all at once.

1. Shifter Pivot Bushings (5-Speed)

The pivot bushings sit at the point the shifter rotates on. When the factory rubber wears, the shifter can move around its own pivot before it moves the linkage, which shows up as a loose, vague knob.

Kartboy's polyurethane pivot bushings are direct replacements for the OE parts. They take out play at the pivot without changing shifter geometry. The kit comes in two lengths depending on your car and linkage:

This is a good refresh to do any time the shifter is already out, especially during a short shifter install. Find them in the Kartboy bushings collection.

And 6 speed guys? Don't worry, our 6 speed short shifters come with polyurethane bushings already.

2. Front Shifter Bushing

The front bushing is where the lower shift linkage mounts to the transmission. Any play here goes straight up to the knob, so you feel it as wiggle when you're in gear.

On our shop '04 STI, the factory front bushings had about 150,000 miles on them. They were ok when new, but even before you put on a ton of miles the rubber is soft with a lot of compliance. Combine that with many miles of hooning the rubber no longer holds the linkage firmly in place. If your car is anywhere near that age, yours likely need replacing too.

Kartboy's front bushings are polyurethane, which is a stiffer durometer than factory rubber (95A on the 5-speed version). Unlike the one-piece factory bushing, they come as two halves that press in from each side. That makes the install easier than fighting a factory bushing in and out. Plan on about 30 minutes, working from under the car on jack stands.

Versions are available for most 5 speed Subarus and 6-speed cars (04–21 STI, 07–09 Legacy Spec.B and more)

3. Rear Shifter Bushing

The rear bushing supports the back of the shift linkage where it mounts to the chassis bulkhead. When it goes soft, the whole linkage can shift under load, and that movement shows up at the knob the same way worn front bushings do.

The Kartboy rear shifter bushing is polyurethane and comes with new bolts. It bolts to the factory chassis bulkhead and slides over the shift rod. These fit most 5 speeds since the 90’s and the 6 speed STIS.

Front and rear bushings are best replaced together. With both done, you should notice less knob wiggle right away.

4. Solid Shifter Joint

The shifter U-joint connects the selector rod to the transmission's shift arm. The factory joint uses rubber bushings that wear out, and it is often the single biggest source of front-to-back and side-to-side play at the knob.

Most solid joint solutions clamp the bolt directly against the center. Tighten it fully and the joint binds; back it off to free it up and the bolt loses clamp load and can work loose. The Kartboy joint separates the two. Oil-impregnated bronze bushings are pressed into a one-piece machined stainless steel body, with a stainless crush tube inside. The bolt clamps onto the crush tube, so it can be fully torqued while the joint still pivots freely.

• 6-speed (04–21 STI): Replaces the factory joint and reuses your factory clevis. Plan on 1–2 hours depending on rust and access. A pin punch sized for Subaru's double roll pin makes removal much easier. See the 6-speed install guide.

• 5-speed: On early WRX and pre-'04 cars, the factory clevis is riveted and can't be serviced. Kartboy makes a replacement 304 stainless clevis, sold separately, with a mounting hole for an external neutral-centering spring. See the 5-speed joint and clevis install guide.

Both kits include new stainless JIS hardware and Nylock nuts. The joint does not fit the cable-shift VA WRX. For a full comparison against other designs, read why the Kartboy solid shifter U-joint is built the way it is.

5. Short Shifter

Once the linkage is tight, a short shifter changes how far the knob travels between gears. Bushings and a solid joint remove play; a short shifter changes the geometry.

Compared to the factory STI shifter, the Kartboy unit is longer below the pivot, which moves the shift shaft farther for the same hand movement. It is also shorter above the pivot. Both reduce throw. Each Kartboy shifter is TIG welded by hand in the USA.

If you want short-shift geometry with a stock knob height, the Kartboy x Turn in Concepts Tallboy uses the same lower geometry with a taller upper section.

The install is nearly the same across 04–21 STI (GD, GR, VA); only center console removal differs. A few tips from our install:

• Put the car in reverse before removing the reverse lockout roll pin. The lockout cable stays in position on its own.

• Use a small-diameter punch for the roll pin, and tuck paper towels around the area so it doesn't disappear.

• You'll need internal snap ring pliers. A flathead screwdriver helps finish the job.

• Transfer the reverse lockout, spring, boot retainer, rubber spring seat, ball cup, and retaining clip to the new shifter on the bench. Grease the ball cup.

• Point the circlip ends toward the driver's seat so they're easy to reach.

• The shorter shifter leaves slack in the reverse lockout cable. Use the second included zip tie to secure it under the car, away from the driveshaft.

Full steps are in the 2004–2021 STI short shifter install guide. Shop all models in the short shifters collection.

Doing Them Together

The shifter, joint, and front bushing all come apart in the same install, so it's much easier to do everything at once than to go back in later. 

All parts are available at kartboy.com. For fitment or tech questions, email supportboy@kartboy.com