How to Install the Kartboy Short Shifter — 2015+ WRX (Cable Shifter)

This guide covers installing the Kartboy Short Shifter on 2015 and up WRX cable-shift transmissions. This install is done on a 2016 WRX but applies to all 2015+ cable-shifter applications. Everything in this guide happens underneath the car — you're swapping the shift plate on the transmission itself.

Kartboy also offers this shifter as a combo with the Cable Shifter Lock, which installs from inside the cabin into the selector mechanism and further tightens up neutral-position slop. That's a separate job covered in its own guide — this one is strictly the under-car install.

 

Parts in This Install

 

New hardware is included with the kit. Don't throw it away.

 

Install Time

 

1–2 hours depending on rust, access, and how stubborn your bolts are.

Difficulty

Intermediate

 

Tools You'll Need

 

  • 17mm socket (front crossmember bolts)

  • 14mm socket (rear crossmember bolts and downpipe mount bolt)

  • 12mm socket and wrench (heat shield and shifter bracket bolts)

  • 12mm ratcheting wrench (the top bolt on the shifter bracket is buried — a ratcheting wrench earns its keep here)

  • Long/deep 3/8" ratchet with a shorty socket

  • Angled box-end wrench

  • Pliers (for the retaining clip)

  • Flathead screwdriver

  • Small punch or roll pin punch

  • Hammer

  • Penetrating oil (PB Blaster, Kroil, etc.)

  • Automotive grease

  • Gloves — the exhaust heat shield edges are sharp sheet metal

  • Regular hand tools for final bolt press assembly (a spare bolt, washer, and nut, or the ones included in the kit, to press the new bearing into the cable)

 

Before You Start

 

You don't need to support the transmission for this job — it stays bolted in on both ends the whole time. Just be mindful working underneath it.

 

 

Step 1 — Remove the Transmission Crossmember

Get underneath the car. The crossmember has to come out before you can get anywhere near the shifter cable.

Take out the two 17mm bolts up front, the four 14mm bolts in the rear, and the 14mm bolt holding the downpipe mount. Once those are all out, the crossmember drops free as one piece.

If your bolts have been in there a while, expect some resistance — a little penetrating oil and a breaker bar go a long way here.

 

 

Step 2 — Remove the Exhaust Heat Shield

With the crossmember out, you'll have a lot more room to work. There's a heat shield covering the factory shifter arm mechanism — it comes off with four 12mm bolts (one of them is up top and hard to see).

Wear gloves for this part. The edges of this shield are sharp sheet metal, and it's easy to cut yourself reaching around it. An angled box-end wrench helps get at the top bolt if it's tight on space.

Once the shield is off, you'll be looking directly at the factory shifter arm — that's the piece the Kartboy shifter replaces.

 

Step 3 — Clear the Way to the Shifter Cable

Some cars have an L-shaped guide bracket held on by three bolts that blocks access to the shifter cable. If yours has it, remove it now before moving on.

 

 

Step 4 — Remove the Shield and Expose The Shifter Arm

This is the fiddly part, so take it slow.

  1. Remove the retaining clip on the shifter cable with a pair of pliers




  1. The third bolt holding the shifter arm is buried up on top of the transmission and is genuinely difficult to reach — this is the same on every 2015+ WRX cable-shift car. A 12mm ratcheting wrench gets you started; if it won't break loose, put a second wrench on the end and give it a tap with a hammer.


  1. With that bolt out, pull the clip, move the cable out of the way, and drive out the roll pin holding the factory arm to the transmission selector shaft.


  1. Pry the shifter arm off. This can be difficult depending on your car and how stuck it is. Kroil was help for this install, so that or a similar product is recommended.

You'll notice the factory arm is heavier and bulkier than the Kartboy piece. The Kartboy version is more compact, and the shorter distance between the roll pin and the pivot point is what gives you the reduced throw with the same cable movement.

 

Step 5 — Transfer the Roll Pin

 

Tap the factory roll pin partway into the new Kartboy arm by hand first — just enough that it's retained but not so far that it blocks the selector shaft from seating.

 

Step 6 — Install the New Kartboy Shifter Arm

 

Slide the new arm up onto the transmission selector shaft and line up the pin holes. Using a punch, drive the roll pin the rest of the way in until it's flush.

 

 

Step 7 — Press the New Bearing Into the Cable End

This is the step that trips people up the most, so pay attention here.

First, pry out the factory soft rubber bushing from the end of the shifter cable with a flathead screwdriver — it should pop right out.

The new bearing is a press fit into the cable end, and you won't be able to seat it with your fingers alone — that's by design. Thread a bolt through the bearing, add a washer, thread on a nut, and tighten it down. As you tighten, the hardware pulls the bearing into the cable end for you. Snug is enough — you don't need to go crazy on it.

A little grease on the bearing before you press it in doesn't hurt.

 

 

Step 8 — Reinstall the Shifter Cable

Reconnect the cable to the new arm: washer on, retaining clip in, then drop the outer clip back down over the cable and make sure it's centered.

 

 

Step 9 — Test Before You Button Everything Up

With the crossmember and heat shield still off, run through the gears and confirm everything shifts cleanly. If something feels off, this is the easy time to fix it — much easier than pulling the crossmember back off later.

 

 

Step 10 — Reinstall the Heat Shield and Crossmember

Put the heat shield back on and reinstall the transmission crossmember, torquing the 17mm front bolts, 14mm rear bolts, and 14mm downpipe mount bolt back down.

 

 

Feel the Difference

Get the car back on the ground and run it through the gears. Throw is noticeably shorter, the gate feels tighter, and there's a lot less play than stock. Paired with the Cable Shifter Lock from inside the cabin, slop in neutral drops even further.

It's a cheap, easy install and one of the best price-to-feel upgrades you can make to a cable-shift WRX.

Questions? Email support@kartboy.com — the team will get back to you.

Watch the full install on the Kartboy YouTube channel (swap in the actual video link before publishing).

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