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I was getting off working a few days back, and when I started the car I realized that the DCCD is affecting the newly installed stereo unit. For a minute, I was playing with the DCCD and switched to Manuel mode while the car is warming up. I backed up slowly and I felt the gears are making these “Cranking / Grinding ” sound and causing the car to jump like its was stalling. In fact, I think it is the rear diff. gears are having a hard time to engage :eek: . I have switched back to Auto and haven’t played with the DCCD since the incident. The problem never resurfaces again. My questions are:
1.) Have anyone experience this event?
2.) What might have caused this to happen and how to avoid from happening again?

Regards
Nim

P.S. the STI is new with 990 miles on and it is taking with care.
 

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Never had that happen, but I stay in auto most of the time. I have heard/felt some clunking with it in manual mode during slow-speed turning--that's normal.
 

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normal. just remember to click into AUTO mode before slow turns where you are not hard on the gas - parking lots and turning into your driveway for example. Then just click back to MANUAL. youll get used to it - know when to either use the gas, or when to disengage into AUTO. (if a manual setting is suitable for your particular driving style)
 

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yes it is normal... manual mode will cause it to clunk and such. I had the same thing when turning at slow speeds in parking lots under 55/45. Dont worry nothing is being damaged - as long as you're not grinding gears or anythign when you shift, but i doubt u are.

Robert~
 

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I'm having a similar problem. I noticed it on my car after a hard launch (rode the clutch, not dumped on AUTO mode). There is a lot of crankling when turning, specially to the right. It feels like the car is getting stuck. Is this really normal?
This is the first time I play with the DCCD and it really sounds like something is broken down there and I'm afraid to drive the car like this. As soon as I switch into Auto mode, it doesn't do it anymore.
I'm going to crawl under the car tomorrow and look for anything wrong/broken. Any tips/advice on what should I look for? Is the DCCD inside the tranny? Sorry if this questions sound stupid, but I'm new to the DCCD stuff. Should I only switch into MANUAL mode on a straight line?

Thanks in advance
-dp
 

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Here's what my subaru tech told me:
The DCCD on auto will change the power distribution based on how your wheels are turning. In a straight line you'll get 50/50 but as soon as one side is rotating faster than the other the computer will kick it into 35/65 to make it easier to turn. It you drive with the DCCD on manual and have it a 50/50 locked (all the way forward) you hear the differential trying to equalize your wheel spin on a slow tight turn, thus the grinding popping sounds. Also he told me the front differential is something unconventional that Subaru came up with and he's never seen any other differential like it. I'll give him a call on monday to ask exactly what it is, now I'm curious again about how this works.
 

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My STi dyno results, 281whp 307wtrq!

This sounds like what happens when you have a 4x4 in four wheel drive on pavement and make a turn. It's not desirable to do this. It sounds to me like in manual mode, the power distribution is not able to adjust correctly. I don't really know how the DCCD on the STi works, but I think I would keep it in auto mode rather than do this to the car.
 

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Manual mode puts the diff in lock, just like with part time 4x4, or like welding your diff solid. Basically, all the tires have to turn at the same speed, so when you turn it clunks..... wears your tires after a while too.

Just keep it in auto when you turn. Even if you're not turning tight enough to clunk you're still stressing the components and wearing stuff more than you need to...


My thought is that on dry pavement there's no reason to be in manual.... the less traction you get the more lock you can use efficiently. On ice or snow, 100% lock is just fine....
 

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Well, after doing a lot of reading here and in NASIOC, I think this is just normal for the DCCD. Thanks guys! Saved me a trip to the dealership.

-dp
 

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bitabur said:
Manual mode puts the diff in lock, just like with part time 4x4, or like welding your diff solid. Basically, all the tires have to turn at the same speed, so when you turn it clunks..... wears your tires after a while too....

Puts which diff in lock?

The center, front, or rear?
 

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I'm pretty sure it puts all in lock...

Otherwise it wouldn't chirp when people are turning out of lots and stuff.....
 

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hughbob said:
Here's what my subaru tech told me:
The DCCD on auto will change the power distribution based on how your wheels are turning. In a straight line you'll get 50/50 but as soon as one side is rotating faster than the other the computer will kick it into 35/65 to make it easier to turn. It you drive with the DCCD on manual and have it a 50/50 locked (all the way forward) you hear the differential trying to equalize your wheel spin on a slow tight turn, thus the grinding popping sounds. Also he told me the front differential is something unconventional that Subaru came up with and he's never seen any other differential like it. I'll give him a call on monday to ask exactly what it is, now I'm curious again about how this works.
Is it true that the mechanical slip kicks in at corners on manual mode?
 

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hughbob said:
Here's what my subaru tech told me:
The DCCD on auto will change the power distribution based on how your wheels are turning. In a straight line you'll get 50/50 but as soon as one side is rotating faster than the other the computer will kick it into 35/65 to make it easier to turn. It you drive with the DCCD on manual and have it a 50/50 locked (all the way forward) you hear the differential trying to equalize your wheel spin on a slow tight turn, thus the grinding popping sounds. Also he told me the front differential is something unconventional that Subaru came up with and he's never seen any other differential like it. I'll give him a call on monday to ask exactly what it is, now I'm curious again about how this works.
Is it true that the mechanical slip kicks in at corners on manual mode?
 

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This herky-jerky stuff should only occur with the adjust wheel in full-fwd poz (i.e. lock). In lock it makes it just like a 4X4 truck in 4-lo, except most stock 4X4 trucks have open frnt diff's where the STi has a limited-slip (in fact all 3 diff's are l/s). So, just like in a 4X4 truck, running in lock-mode is not recommended for paved roads (it says so in the manual)! I'm guessing this mode is mainly for rally guys who get stuck in mud on the side of the road or in a snow-bank, etc - just what you'd use 4-low for in your 4X4. The other settings should'nt make these sounds (mine doesn't), but I agree, auto-mode is best for regular driving. One cool thing: I tried setting the wheel all the way to the back to hang the rear out in a recent rain, but I think the traction-controll was preventing it, and so it just plowed the front-end (understeer) making me go straight instead of turning the corner. Kinda cool, but you better have room on the outside!
 

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Re: Red .2 light bulb condoms

FYI - On my 02 WRX the center diff went out, and it started jerking side-to-side in tight turns - like I had a bad limited-slip rr diff unit, but it was the center-diff. Of course, that car had no DCCD, but it acted counter-intuitively so I thought I'd mention it.
 

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mine makes noise when set to anything but auto, but only when turning sharp and at low speed (such as parking)

i also get the most wheelspin, sometimes front, in auto
 

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SAMCO turbo inlet pipe, red

Come to think of it, I never tried sharp/slow turns in any of the manual settings. I just tried it during moderate-speed cornering. Not surprising that it does, given how it works I suppose.
 

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traction control? i've used it locked all the way back on autocross courses, and it's really easy to get the rear end out wet or dry. i found it quicker for sure on the autocross course w/ it locked, and the wheel all the way back, but i haven't tried adjusting it forward at all...soon.
 
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