Hi,

I have had this problem since day 1 I bought the car new. It is a STi 07. I have taken it to Subaru Ossie park with this problem. First they said it was normal, then last year before the warranty run out, I took it back to query it, as lots of people who hear it say its not right... They replaced the rear struts saying they were knackered, but the sound continued as again they said it was normal.
Anyway after my 50k service around Christmas, the big $750 major service one, telling them about the same problem, they said there was nothing wrong. But I got the car back and it sounds like a knocking when I take off, sort of like when you put shit fuel in a car and take off slow and in low rpms... But it sounds like its just under the shifter. If I rev it a bit harder and feed the clutch out it goes, same with this clunking noise when I take off in first left or right, that disappears as well.
So I take it to Subaru today for the knocking noise, and the tech picks up on the clunking noise when I take off and says it isn't right, mind you the knocking noise didn't occur!
They took the gearbox off and apart and said that was fine, and that it might be the rear diff. They wanted it for 5 days to take the entire rear diff apart, and I said no unless you can give me a loan car, so needless to say I have the car back atm.
I feel now the car is out of warranty they are trying to sting me for something that was obviously wrong from day 1. But reading other people on the net, they have been told this clunking noise when taking off in first moving left or right is normal!!
Can anyone shed some light on this? or at least advise of a third party mechanic that knows what the hell is going on? I feel Subaru are pissing me around. Or maybe I'm wrong and there is no issue.

Sobo

Rear diff bushings would be my guess. The stock ones are crap and flex causing driveline chatter.

Go see Doug and Damien @ STechnic. They'll tell you what it is in under 30 minutes or your pizza is free!

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[COLOR="Gray"]550Nm off a 2L... Just wish it was in the dak dak...[/COLOR]

cool mate, thanks for that. Just booked it in with them!!

Put your DCCD in manual mode and move the thumb wheel so its fully unlocked and sending more torque to the rear.

Go for a test drive. If the knocking still occurs then Id be looking at diff bushings or something like the steering knuckle touching the dump pipe.

If the knock is gone then the knock you heard before is just the DCCD unit binding up. This is normal. I dont think the OEM DCCD auto mode handles tight turns very well on take off or in car parks. As you feed in more throttle it will try to stabilise the torque split by increasing the dccd lock up.

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RS Liberty - Because WRX's are only good for parts...

^^^ WHS, I agree with this, try that and it does have an effect I would say definitely sounds like normal dccd operation. They do tend to clunk a bit

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Its just the internet dude, its not real.
F.B. Racing
01 WRX (STI badged)
2010 XR5 Focus
06 Impreza Hatch 2.0i

I thought this was more prevalent with 05 STi's, havent heard of any 06/07 ones doing it before.

My 06 doesn't do it at all.

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EBISU SUBARU, SHIBUYA-KU TOKYO

I tried that before, but anyway...

I just tried it again then, and it's quieter in manual all the way to the rear, not as noticeable but still does it. Seems that it does it more if it bogs off the clutch.

Tried it in auto vs manual, good launch, bad launch... Auto is a lot louder and clunks longer, I also noticed that it also does it going straight as well.

If I do a perfect launch, it's not there...

So I guess in essence, I should just replace the bushes with those hard $32 ones and use manual mode ? If I don't want the sound?

yeah, Id say its DCCD binding up.

Theres not really a lot you can do about it. Doug @ S-technic could disassemble the DCCD unit and inspect it for you.

Also you can try using a different gear oil in the gearbox and rear diff to see if that shuts it up.

Personally I wouldn't worry about it. I wouldn't even regard it as a fault with the DCCD operation.

Something to also consider is rear diff backlash. The more DCCD binds up the more noise the rear diff makes.

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RS Liberty - Because WRX's are only good for parts...

Cheers, I'll take it to Doug anyway.

But seeing it's done it for four years and I haven't noticed anything but that annoying noise, I'm sure it's not terminal.

Cheers guys for your input, I'll turn the stereo up louder until Doug looks at it

I suspect the reason Subaru took so long to release DCCD and mechanical rear diffs on the Australian market has something to do with the noises and harshness associated.

It's worth the compromise if you use the car where wheelspin is expected, ie; track, skidpan, competition etc. but it's a bit of a pain in an everyday car.

I'll have a look/listen and we'll see what the go is.