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Kartboy Rear Diff Crossmember Bushings Standard Set (Part Number: )
Kartboy Rear Diff Crossmember Bushings Standard Set (Part Number: )
Kartboy Rear Diff Crossmember Bushings Standard Set
Subaru Models (inc. 2002-2007 WRX/STi)
Read 13 Reviews | 7 Q&As
Part # KB-003-DIFF

In stock! Ships same day

Features & Product Details

On this page, you are looking at the Kartboy Rear Differential Crossmember Bushings in the Standard Set.

If you are experiencing rear clunk of your 2002-2007 WRX/STI, you may want to consider a set of Kartboy rear diff cross member bushings! You will notice improvements in acceleration, deceleration, and these are made out of hard urethane that will reduce deflection and absorb more shock.

These Kartboy bushings are handmade in the U.S.A. and are guaranteed.


Brand: Kartboy
Bushing Location: Outrigger
Installation Hardware Included: No, reuses OEM
Material: Urethane
Mfgr. Warranty: Limited Lifetime Warranty
Condition: New Product
Return Policy:

RallySport Guarantee - 30 Days

Items that are covered under the RallySport Guarantee offer a 30 day no questions asked return policy.

RallySport Guarantee items may be returned within 30 days of the original invoice date and must include all the original parts and contents for a refund.

The RallySport Guarantee does not apply to products that have been modified, damaged, misused or abused. All returns require an RMA (Return Merchandise Authorization) Number, and freight charges are strictly non-refundable. For more information regarding our freight refund policy, please refer to our return policy page found HERE.



13 Reviews
4.2 out of 5 Stars
5 Stars
4 Stars
3 Stars
2 Stars
1 Stars
Customer Photos and Videos
No user media. You can upload a photo or video of your install by posting a review.
Slight Difference 3 years ago
5out of 5stars

Some people don't notice the difference in these, but it is there. through corner acceleration there was less rear end drive train movement and vibration. If you know what you are doing and what these are really meant for, get them now!
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0 of 1 people found the following review helpful
These instructions are garbage 4 years ago
3out of 5stars

heres how you get instructions for this: WHAT KIND OF CAR IS THAT? seriously print out some instructions and put them in the bag next time that tell your customers which bushings are used for each chassis type and in what location.
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1 of 3 people found the following review helpful
thanks for nothing 4 years ago
1out of 5stars

just to start things off i wish i could give these a 0 star review. well first off wheres the installation instructions,oh on a crappy forum, thanks. second i know these are universal but guess what? my 05 sti look nothing like a legacy, so you just caused me a ton of confusion. third do these go to the diff support bracket at the rear, the front of the rear diff? where? i love crawling under my car and trying to compare my drivetrain to a legacy(pictures provided). all in all, just buy the perrin lockdown kit. instructions and only the parts you need. ill never buy kart boy again.
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1 of 2 people found the following review helpful
Good product  4 years ago
5out of 5stars

i don't drive my car hard enough to notice a difference but they are better than the oem ones
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1 of 2 people found the following review helpful
upgraded! 7 years ago
5out of 5stars

Any time doing something towards the rear diff or swapping drive shaft, why not change these. Better safe than sorry.
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  • Q: just to be clear  Tim P.4 years ago

    These go between the cross member and the frame above the differential carrier right? Not the outriggers under the back seats. Above the cross member would require 4 bushings or 2 kits right? These look similar to the oem but the oem has a metal sleeve around their's.
    • 0 of 0 people found the following answer helpful

      A:  Correct, this will attach to the outrigger/crossmember mounts between the subframe. For better information Kartboy has an installation guide on their website. This is used in conjunction with the OEM bushing to help fill voids.

      Nick S. @ RallySport Direct 4 years ago  
      Was this answer helpful?
  • Q: Fitment question   driftingrotaryz187195 years ago

    Fitment question, is this suppose to eliminate the metal plate that's found above my rear diff crossmember on my GC?
    • 0 of 0 people found the following answer helpful

      A:  No these will not remove anything these are simply inserts to help prevent diff clunking.

      guest57853c642a8d25b5018c44a7 @
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  • Q: Legacy GT fitment problems  Charlie Tango5 years ago

    I have an 07 Legacy spec.B on which I tried to fit this part (KB-003-DIFF) onto; however, I could not find a correct place anywhere on my car to install it. I called my tuning shop, they weren't any help. I called Whiteline (because I didn't have time to email Kartboy and wait for a response), they didn't have the right information. Is anybody sure this part actually fits on my car, and if so, where? Thanks.
    • 0 of 0 people found the following answer helpful

      A:  Pull the plate where the ARB is on each side for one set. Then in front of the tow arm in the front will be the same thing. pull the plate and place a bushing in there. You will use 4 of the bushings that are the same thickness.

      Kirill C. @ RallySport Direct 5 years ago  
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  • Q: Are these the same as the Rear Diff Lock Bushings?  laplacexformofs127946 years ago

    I have heard the Rear Differential Lock Bushings called about 20 different things, and there are around 3 different companies that make bushings that look very similar. Are these the Lock Bushings? Thanks!
    • 2 of 2 people found the following answer helpful

      A:  These bushings go in the same location as Whiteline's Rear Diff Support Lock Bushings.

      Zach G. @ RallySport Direct 6 years ago  
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  • Q: install only this?  dman7037 years ago

    Hi I am wondering if it would be beneficial to install these but not the differential mount bushings (turn in race). I am looking to install either one, which is easier to install, quieter, and will give better performance?
    • 2 of 2 people found the following answer helpful

      A:  I think that these would be easier to install, and quieter as well, but I also think you would see much greater performance with the rear diff bushings, as that will have more of an affect on the rear diff movement than these would. Thanks, Rick

      Rick C. @ RallySport Direct 7 years ago  
      Was this answer helpful?

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