porkchop-rob

Hello fellas. I purchased my first cadillac a week and a half ago and Im loving it. I picked up a 2007 cts-v in black with 75k on the clock. This is by far the fastest car I have owned, and after driving a civic for a year and a half, this thing is a BLAST.

My only concern is a noise i hear under hard acceleration when i let off the gas or clutch to shift. Each time i hear a loud bang or boom sound. It is way worse in the lower gears.

Here is a short video of the sound taken by my phone.

Any help is greatly appreciated.

http://www.youtube.com/watch?v=outAI...e_gdata_player

98cobra

iTrader: (32)

Check the motor mounts

porkchop-rob

Hate to ask such an amateur question...but what is the.best way to check. Am i looking for engine movement under load or am I looking at the mounts themselves for visable issues?

lollygagger8

iTrader: (7)

Look for brownish residue from the gel that comes out of them after the break and leak. It almost looks like an oil leak. The fluid is actually green before it dries into a brownish hue.

azn2dmax

iTrader: (33)

its hard to see if the mounts are visibly bad. Not a lot of room to see. Do look for excessive engine movement though. I changed my MM with UMI MM and love them but some people dont like them.

One of the problems in the V is the "clunk".


One of the upgrades to do is a short shifter if you dont have one ASAP. Hint hint. Buy one form me. LOL Shameless plug

https://ls1tech.com/forums/cadillac-...fter-70-a.html

punishmentcycle

iTrader: (6)

Diff bushing.. Jack up the car and push up on the front of the diff.. It'll prolly move a whole inch up and down. Any of the aftermarket bushings will solve ur problem

rjoffe

This is also known as the "parade clunk". There are a whole host of reasons. Some have been mentioned above, but here is my list (in no particular order):

Engine Mounts
Tranny Mount
Diff Mount
Driveshaft coupler
Driveshaft bearing
Two piece flywheel

kl2onik

iTrader: (3)

Mine did the same with only 50k on it when I bought it. The motor mounts are most likely the problem plus you rear dif almost bottoms out cause of the bushings and wheel hop. If they are shot as bad as mine were, one side of my engine would almost come up and hit the ls support bar over the engine bay under hard accel. The motor mounts may look fine till you take them out. I went with the stock mounts again knowing they will have to be changed down the road since I'm skeptical of a stiff ride/road noise with the umi's. If you do get those there is a guy selling them on cadi forums for like 150. I know what you are going through cause it scared the $hit out of me the first time I drove this car hard, after my m3 this car sounded like going on a bad hay ride.

porkchop-rob

what caddi forums?

do you know the guys screen name?

i will replace with poly mounts if needed.

kl2onik

iTrader: (3)

cadillacforums.com look in the classifieds. I hate that site but thats just me.
here is the link directly just cause I woke up on the right side of the bed today)
http://www.cadillacforums.com/cadill...nts-21-21.html

porkchop-rob

thank you.

greatly appreciated.

EdmundGTP

maybe it's just me but i couldn't discern a damn thing relevant to the OP from that video.

porkchop-rob

If you turn up the volume, just as i let off the accelerator, and clutch, there is a boom. It not only a noise, but i can feel it in the car. I will get the car off the gtound and check the motor mounts as well as the diff bush. asap.

serik21

Check your diff
Bolts as well if it ain't your diff bushing but it's prolly the diff bushing.

meatyCTS-V

$20 says it's your motor mounts.

while you're doing them, also do your transmission mount.

Creative steele sells the whole shebang for like, $350ish.

A worthwhile investment, if you as me, good sir. I have mine in, and love 'em.

-meaty

odthetruth

iTrader: (4)

I'd go UMI motor mounts, and CS trans mount and be done with it. I'm pretty sure its the mounts also.

Racer001

iTrader: (15)

Same symptoms I had due to bad motor mounts.

I did the UMI motor mounts and Creative Steel transmission mount. My car feels TOTALLY different now. No more clunks or bangs. I can now rip through the gears because my transmission will shift now, as before it would get hung up between gears!


Best thing I've done to the car.

Brackets

My money's on the diff bushing.

sod

iTrader: (1)

when I got my '05 with just under 50k on it, it did the same thing.

My buddy asked if there was a bowling ball rolling around in the trunk.

New motor mounts & diff mount (stock) & the clunk is gone. 2 years later & it's still gone.

TokyoJoe

Ah ****, nice. I was wondering what that was. I have a similar issue with mine, if I slip the clutch nice and slow it wont do it, but if I engage the clutch quickly I hear it.