Hi guys,
I have an 04/05 WRX that is making a knocking noise from the rear end. When you take off slowly you can feel the rear right hand side drop slightly. I have taken the car to a reputable suspension place and they said they couldn't figure out what the noise was and recommended starting to replace bushes that were going to cost a fortune with no guarantee that it would fix the problem. Have any of you had a similar experience with your WRX's ? my gut feeling is it has something to do with the struts as i have read this can be a common problem with this model. Any help will be appreciated.
Cheers.

My MY04 STi has this exact same noise, comes from my rear left wheel and only makes noise when your driving relatively slowly and the wheel goes over a bump or something on the road, but once cruising its okay.
very keen to fix this also!!

Sounds like one off the rear shock struts is sticking
common problem
had one off my rear shocks do the same thing on the rear of my wrx wagon
I replaced all my shock struts and installed new lowered springs while it was done
Not had any problem with knocking since replacement ... Have search on the forum in Mechanical section

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Looks like it's a common wrx rear strut problem where a portion of the strut shaft isn't getting grease, and therefore knocking against the housing. you could install a grease nipple onto the strut housing like this https://www.youtube.com/watch?v=zYiP4DG_OQU to fill the gap with grease and stop it knocking the sides, or replace new shocks or get some coilovers.

Thank's for the response guys! That you tube video link you sent through is great. I am pretty confident that this is the problem. The suspension hasn't been touched since i have had the car so i think i will start with the struts.

Cheers.

Could be rear swaybar needs lubricating

Mine has coilovers and is a 2012 sti...It knocks too. I've lubricated them with some spray, worked for a few weeks then comes back. I've learnt to live with it

so there's no damage done over time to the suspension by living with this? because I am about to install a grease point on the rear shocks this weekend but if its just a noise issue ill live with it until I upgrade to some coil overs. Or at least if i get new springs in the meantime I'd rather do it then while the shocks are off the car.