[sti_schumacher]

Hey guys.

I have a stock setup on an 04 sti.
I noticed that when i'm driving normally and then let off the gas (or gently apply the brakes), there's a single 'knock' sound, coming from somewhere at the back (not entirely sure - could be from the center). This doesn't happen under any other conditions. Noise most likely coming from the drivetrain.
What could it be???

[BenW]

might be brake pad knockback, mine will do it sometimes when coming to a stop, reversing, then when I touch the brakes after the change in direction, it will make a small pop.

[sti_schumacher]

Originally Posted by BenW

might be brake pad knockback, mine will do it sometimes when coming to a stop, reversing, then when I touch the brakes after the change in direction, it will make a small pop.

yeah, but the knock in my car moslty happens when i downshift slowly, at a slower speed. It sounds like a gap is being filled between two moving parts, when one is moving faster and the other starts moving slower and then bumps into the other one to make it follow. Specifically, this noise happens when i start releasing the clutch after a downshift- so it could be something like a driveshaft in its housing (???). And it's not necessarily after any turns....
Any other suggestions?

[garamas]

i had the same problem in my car had the dealer replace bother rear shocks with new ones thinking it was strut clunk

still made the sound

i do have a aftermarket exhaust on the car so what i did was re align the exhaust cause it was sitting a little off center and that completely fixed the problem

[psuLemon]

if you aren't smooth shifting, it could be your differentials.. they tend to make noises.

[PartySTi]

Mine is making the same noise.. Getting it checked next saturday. My guy says it probably a lose bushing or something stupid.

[jays05]

Re-torque the axle nuts.

[supermarkus]

Originally Posted by BenW

might be brake pad knockback, mine will do it sometimes when coming to a stop, reversing, then when I touch the brakes after the change in direction, it will make a small pop.

I don't think that is knockback that you are describing, that's just pads shifting in the caliper. Knockback is usually experienced on the track or under hard driving situations. You'll have to step on the brakes to move the pads back into position before you actually brake. They get knocked out of position by the rotor due to the flex of the hub/bearing assembly.

OP is probably hearing drivetrain lash or the slop from the soft rear diff subframe bushings. I hear all that plus my struts knock. I've learned to ignore it and can fix it when I really want to.

[sti_schumacher]

i replaced my driveshaft w/ an aluminium one, and it seemed to have went away...

ill check again

[V8HungrySTI]

So would this knocking sounds from the rear under low speed or shifting be the drive shaft just adjusting its self... because i have the same issue... sigh