Downshifting Clunk?!?!?!

**hieu1004** · 04-06-2010 08:21 AM

So I was merging on the freeway this morning on my way to work when I realized I was in 5th and just kind of cruising along at 55-60mph when I needed to speed up and merge.

I downshifted to 3rd, did not have time to double clutch because I needed to go right away! When I did so and accelerated, I heard a big clunk/thud towards the back of the car. Made me cringe...hopefully I didn't hurt anything too bad....

From my search, I believe the clunk was my rear diff. from the hard downshift?? How bad is it and do you guys have this problem? This is my first AWD so I am learning all the nuisances that come with it.

I know double clutching will help keep the shifts smooth, is there anything else I can replace to reinforce whatever is making the sound?

**oguitar** · 04-06-2010 07:43 PM

Just curious. Did you by accident downshift to third or did you do it intentionally?

**EJ257** · 04-07-2010 04:54 AM

Turn-in Concepts

Call them and explain you're experiencing an issue with rear differential clunk. They have a "Klunk Killer" package for previous MYs, maybe they can set you up. If not, they'll tell you what to buy. After they tell you what to buy, pull out your credit card and order everything they said (I'm not kidding).

Besides that, learn to drive without shock-loading the transmission (the bushings will just mask the problem), which just takes practice.

**hieu1004** · 04-08-2010 08:44 AM

I downshifted intentionally. I am usually really good about shifting smoothly or by rev matching. It was 5am and I was on my way to work so I guess I was lazy & tired.

Again I am new to AWD so I am still learning all there is to know.

I just need to be more careful in the future.

**lytlec** · 04-08-2010 08:54 AM

Is it really necessary to double clutch in our cars? I thought we had synchros...oh well! Just seems a little unnecessary to me!

**hieu1004** · 04-08-2010 09:11 AM

Originally Posted by lytlec

Is it really necessary to double clutch in our cars? I thought we had synchros...oh well! Just seems a little unnecessary to me!

No it's not neccesary (of course it is debatable by many), its just a habit that I have picked up over the many years of driving and sometimes I do it just because.

Rev-matching simply makes it less jerky and smooth when downshifting, but really, it is not necessary either.

**lytlec** · 04-08-2010 09:17 AM

Originally Posted by hieu1004

No it's not neccesary (of course it is debatable by many), its just a habit that I have picked up over the many years of driving and sometimes I do it just because.

Rev-matching simply makes it less jerky and smooth when downshifting, but really, it is not necessary either.

I will be honest...I do rev match...but usually only when going around corners or when slowing down.

**mangostick** · 04-08-2010 09:37 AM

I go 5th to 3rd quite a bit.. never got a clunk while doing it though. .. hmm.. only once have I heard the "clunk" out of my 2010.. it was shifting up into 2nd on a bumpy surface under hard acceleration. Scared the crap out of me because no sooner did I get the clunk, the traction control snipped the balls right off of it.. I thought I broke something till I quickly realized the tc warning light on the dash. Doh!

as said though, I haven't had the clunk since.. rev matching goes a long way to keeping driveline components in one piece. I might look into the "clunk" kit that tic has .. or a variation they recommend for the later cars. Especially since as the car wears in the "clunk" will most likely become quite a bit more apparent.

**hieu1004** · 04-08-2010 11:00 AM

Originally Posted by mangostick

I go 5th to 3rd quite a bit.. never got a clunk while doing it though. .. hmm.. only once have I heard the "clunk" out of my 2010.. it was shifting up into 2nd on a bumpy surface under hard acceleration. Scared the crap out of me because no sooner did I get the clunk, the traction control snipped the balls right off of it.. I thought I broke something till I quickly realized the tc warning light on the dash. Doh!

as said though, I haven't had the clunk since.. rev matching goes a long way to keeping driveline components in one piece. I might look into the "clunk" kit that tic has .. or a variation they recommend for the later cars. Especially since as the car wears in the "clunk" will most likely become quite a bit more apparent.

Ya I know what you mean. Our car makes all kinds of interesting noises.

**Crb03** · 04-08-2010 11:20 AM

Get the TiC or perrin clunk killer works like a charm. And yes most basic manual transmission made today have synchronizers. Some even have one on reverse gear.