[CaQuin]

And then the traction light (I think that's what it is) blinks for a bit. That thud scared the hell out of me... Normal?
Car runs fine.

This was going from 1st to 2nd. I don't think I'm going to do that for a while.

This was my first real real push after breaking the 1000 break in.

Thanks in advance.

 

[mangostick]

Under hard acceleration? Came from rear of the car? ..You've been the recent victim of diff clunk!

But there's hope my friend

ok, all bs and joking aside what you experienced was indeed what we call "diff clunk". The factory diff mount bushings are soft to keep nvh to a minimum (noise, vibration, harshness) and for that they work, but when forcing full power down the drivetrain the diff will move around on those soft bushings. I found the same issue with my 2010 just after the break-in too. Diff bushing replacement or what is easier would be diff mount bushing inserts. I'm assuming your car is a 2012? If so the parts would be same for 08-12 and you can find them here

2008 Impreza rear diff inserts

tic wont steer you wrong. So far, every bushing/mount under my car came from their stock. I'm not associated, just a very happy customer. If you decide to do them yourself vs a shop.. air tools make things much much easier. Lift wise I used normal run o the mill ramps to get the car off the ground to give me room to work.

 

[CaQuin]

hmmm so new to this.. Diff clunk... interesting... That doesn't mean I damaged the car right? I don't plan to race or mod the car. I just wanted that one hard pull after the break in. I'm ok right? lol

 

[mangostick]

nah, no damage. just the diff running out of movement up against the cross member that locates it. Like said, happened to me a few times too. No big deal, but getting rid of it is simple and inexpensive so why not?

 

[Ingo]

You're ok, so is your car... The traction light does come on and go back out, the back out is the important part... But you can avoid that by turning the traction control off before you do that hard pull. . . it'll keep the car from correcting a slipping wheel by cutting power and maybe even applying brakes...

 

[CaQuin]

nah, no damage. just the diff running out of movement up against the cross member that locates it. Like said, happened to me a few times too. No big deal, but getting rid of it is simple and inexpensive so why not?

That is true. Out of curiosity... By installing that, does that change the nvh?

 

[CaQuin]

Btw, thanks mango!

 

[CaQuin]

You're ok, so is your car... The traction light does come on and go back out, the back out is the important part... But you can avoid that by turning the traction control off before you do that hard pull. . . it'll keep the car from correcting a slipping wheel by cutting power and maybe even applying brakes...

Nice. I forgot about turning off the traction control. That's how noob I am. This car is such a completely different animal than my previous car. I love it! Thanks for the tip/ advice!

 

[mangostick]

No increase in noise over factory. actually, I was quite surprised at that when I did mine. One would think that it should transmit more noise however if you look at how the entire rear cradle (diff/suspension) is installed there are actually 4 more bushings aside of the diff mounts that locate the entire assembly and also work to relieve any noise issues.

I went a step further and also did the cradle bushing inserts. 9's and 10's had soft squishy cradle bushings. The 11+ though were revised to be stiffer.. so you'll likely be able to get away without em. Even still for under $80 and maybe an hour of work the difference is really noticeable, especially at low speeds in parking lots, backing or taking off from a light. There's no more slop in the rear so the car just goes. You'll also find you dont have to use so much rpm/clutch work to get the car moving.

 

[CaQuin]

Sweet! I'm actually considering it now. Thanks again for the info... Real helpful!

 

[mangostick]

no worries man, that's what we're here for. Oh, fyi.. I also did mine almost entirely with hand tools as well.. the only real pita is that front diff mount bolt/nut. That sucker is ON THERE!. I suggest at very least a electric impact gun or air powered impact. I had to use air for mine and it was still pesky. If you buy from TIC they should come with basic instructions too (did mine so long ago I cant remember if they did or did not) so if you're the least bit mechanically inclined and have access to the right tools its a pretty easy job.

 

[Calvinball]

Was there a lot of vibration added?

 

[AmateurX]

Would this help with breaking the tires loose as well? I notice when I have my winters on, I have to turn off the TC on hard pulls. (mostly b/c the tires aren't that great in the dry.) But, if this would help with lessening the instance of "wheel spin", I'd be all for it!

Also, how do these bushings help in parking lot? :confused1

 

[mangostick]

No noticeable change in driveline vibes.. actually on that note I didn't start hearing/feeling anything exta until I did the shifter bushings/transmount and pitch stop. None of which have to be done to mitigate diff clunk. Just further measures to solidify the driveline.

Winter tires have deep tread that tend to squirm quite a bit. Since our traction and stability systems rely on wheel speed sensors to judge if wheels are slipping or have traction the squirmy tread can/does play some tricks on the vdc computer. When I have my winters on I bump traction control very easily too. That's a matter of the tires vs ground rather than driveline vs tires. Unfortunately not much we can really do about that short of driving less aggressively (what fun is that? lol)

What I did notice when stiffening up the rear mounts/diff mount was elimination of that weird independent feeling between f/r wheels under power. The whole driveline now feels like it works together as a unit. I believe it does improve traction quite a bit .. probably allows for the vehicles safety systems to work more efficiently as well since the slop is greatly reduced. Also in doing the cradle bushings the rear suspension and whole feel of the rear of the car is much tighter.