BlackCobaltSS20

I know every one will say "use the search button" but hear me out please. I've read many forums about the clunk that cobalts make when shifting gears and how its "normal for cobalts". I have a 2007 cobalt SS zzp stage 3 and Ive had this problem for a while. When I don't shift perfectly or accelerate to fast it sounds like my engine rocks and makes a metal on metal clunk. Also when I'm in a parking lot going slow in 1st with the accelerator completely released and start to slowly give it gas it this noise will occur again. I've replaced my front train mount a while back to try and fix this noise but it still occurs, my mechanic said the rear tranny mount was. Any help would be great I've read about after market engine & tranny mounts but heard rumours that they make this problem worse because they are more solid for launching purposes.

riceburner

iTrader: (66)

Sounds like one of your mounts is bad.

Replacing any of them with new, oem ones wouldnt hurt ya. Even running aftermarket ones, while stiffer, wont clunk.

There are 4 mounts, usually the lower trans mount (drivers side near radiator) is the one that goes bad.

BlackCobaltSS20

That is the mount that I originally replaced, so I'm debating what to do now because I don't wanna spend money for a new mount and not fix the problem. My top engine mount look a little worn out but that mount is for lateral motion and the clunk happens when I'm going straight.

BlackOnBlackOnBlack

I had a similar noise after I installed clutch and rotated mounts. Turned out the trailing control arm bushing bolts worked loose, wernt torqued correctly...the bolts holding the rear of the sub frame up. Sounded like motor mounts but was actually the whole the front end, mounts and all. Luckily I fixed that one before it was too late. Impacted the hell out of em and all was good

GfSwindle06

My 06 has had the same metal on metal clunk when shifting gears that you speak of for the 2 years I have owned it. I have a powell rotated mount installed and the clunk is still there. I've learned to live with it since nothing bad has happened yet. However I believe it to be either a) excessive transmission gear-train slop or b) an axle that has possibly worn out in the CV joint but I lean toward the gear train since both my axles are smooth when turning at full lock both directions. Another educated guess is that it is slop in the Quaife geared limited slip which makes sense if you look at how a gear lsd works. All those gears sit in machined pockets in the lsd housing accounting for all the tolerances there, through the gears, and then the cv axles themselves, add it all up and when the momentum of these parts are shifted from one way to the other such as cruising through 1st which is the most noticeable and when making a shift when all these parts are free to move about their own momentum without the clutch engaged and you get metallic clunking when all those tolerances are forced from one direction to another.

Kinda winded and lengthy explanation but just something to think about next time you hear it.

QuickShift

I have the same noise on my mostly stock 07 SS/SC ....It has been happening for almost a year now...I am thinking a broken tranny mount because axles seem fine otherwise...Happens when taking off and 1st-2nd shift...

Probably unrelated but the car also starts bucking sometimes when taking off if your not super careful with the throttle....Then you have to get the clutch to the floor right away or it starts getting violent...