CB-4297k - COBB Rear Differential -Subframe Inserts

CB-4297k - COBB Rear Differential -Subframe Inserts

WRX 2008-2021

WRX STI 2008-2021

Type RA 2018

S209 2019

Congratulations on your purchase of the COBB Tuning Rear Differential Inserts! The following instructions will assist you through the installation process. Please read them BEFORE beginning the install to familiarize yourself with the steps and tools needed. If you feel you cannot properly perform this installation, we HIGHLY recommend you take the vehicle to a qualified and experienced automotive technician.

Table of Contents

Parts List

 (2) Differential Inserts

 (2) Washers

Tools Needed



  • 3/8" ratchet
  • 3/8" 17mm socket

Section 1

  1. Park your car in a flat, level area and allow it to cool down properly.

  2. Lift and support your vehicle properly.

  3. Support your differential using a jack.  

  4. We're going to work on one side at a time to prevent the alignment with the holes from being an issue.  Using your 17mm socket remove one of the nuts for the bushing.  We were able tosneak in behind the swaybar, depending on your tools you may need to remove the sway bar from the frame mounts.

  5. Lubricate the parts of the bushing that stick out using the provided grease, then insert it into the bushings in the differential lining up the slots in the bushing with the sizes of the slot on the insert.  This can be made easier if you lift a little weight off the differential with your jack.  There is a bit of a sweetspot though before the it starts to put pressure on the top of the bushing, so a little trial and error and feeling around will help get it in more easily.

  6. Push them in as far as you can, then add the flat washer, then tighten down the factory nut with a small amount of loctite.

  7. Repeat the same on the other side, then drop your car back down, you're good to go!

Contact Us:

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Email: support@cobbtuning.com

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