SS A6 transmission noise when in M mode

[vthokiefan]

Howdy everyone! Proud new 11 CGM 2SS/RS owner here (picked it up yesterday actually). So I know I'm a noob to the forum, but I did try to search for this before starting a new thread without much luck.

So driving home from the dealer I noticed that when I put the car into M mode to use the Tapshift, driving at about 40 mph or more, and downshift into 3rd I start to get a noise from the center console that sounds like little rocks or sand rattling. As soon as I upshift into 4th it goes away. I am assuming it is coming from the transmission; however, it could be exhaust noise/rattle at that rpm. It definitely seems to be linked to either engine rpm/drivetrain rpm. If I can make an audio clip or vid I will try to post it (if that's possible on here).

When I test drove the car prior to buying it (~15 miles total), I don't remember hearing this noise when in M mode.

The car only has 86 miles on it so I'm trying to figure out if this is normal or not... I don't want the first two drives in my new car to be from the dealer and then back to the dealer for service!

[stiletto7]

I have a similar car. I didn't notice any noises until I did an axel back exhaust update. The auto has 4 mufflers, it has the ones you see in the back, and if you look in the middle of the car there is a second set. This second set of muffler is for the displacement on demand feature. I find my car kicks into DoD at certain RPM in certain gears. 3rd gear at about 1800 RPM and my car makes some weird noises. I don't drive in M mode very often, but I think you can turn off the DoD in M mode and see if you still get the noises. While in M mode, down shift a gear, then shift back up. Seems to work in my car as I don't get the noises anymore while I am driving in M mode until I switch back to Automatic or turn the car off.

[vthokiefan]

Thanks for the reply stiletto7 -

Today was the first day I've been able to go out driving again due to thunderstorms every day since I got it.

I did hear the noise some this time but it didn't seem as loud. Not sure if it was cause the car was well warmed-up this time before I tried it or what. It only seems to be noticable when i am in 3rd or 4th under light throttle or coasting... don't seem to hear it when I get on it (probable because all I can hear is the beautiful V8). If anything changes, or if I have to take it in I'll post an update.

[Scott@Bjorn3D]

Originally Posted by stiletto7

I have a similar car. I didn't notice any noises until I did an axel back exhaust update. The auto has 4 mufflers, it has the ones you see in the back, and if you look in the middle of the car there is a second set. This second set of muffler is for the displacement on demand feature. I find my car kicks into DoD at certain RPM in certain gears. 3rd gear at about 1800 RPM and my car makes some weird noises. I don't drive in M mode very often, but I think you can turn off the DoD in M mode and see if you still get the noises. While in M mode, down shift a gear, then shift back up. Seems to work in my car as I don't get the noises anymore while I am driving in M mode until I switch back to Automatic or turn the car off.

Actually it has 2 mufflers and a big ass resonator. I cut that SOB out and put in a X-Pipe and spun the tires more and droped 30Lbs of weight.

[CruznSS]

I took the resonater out also. Heavy piece of muffler, reduces atleast 30 pounds. Replaced rear cans at same time, no funny noises since and I'm at 42,000 miles. Goodluck and enjoy!

Sent from my PC36100 using Tapatalk

[stiletto7]

I can't imagine you don't have any noises. Mine makes all sorts of racket in 3-4 gears with the AFM. I hate the AFM. And I have the extra Resonator still in there. I have to imagine its worse when you take the resonator out! BTW - it only makes the noises if you aren't accelerating hard.

[CyberDan]

I've had that same noise since day one... Does it happen when it hasn't warmed up yet? You might want to look into the heater core inlet valve... I need to take mine in to get that replaced.

[woodside783]

get rid on the amf you love the car so mutch more

[CyberDan]

I get a noise when first starting it up, and driving through the gears, I hear the same sound you're describing. Like rice crispies in the transmission, but it goes away after warmed up... I'm thinking I'll put amsoil or rp in my tranny to see if it helps.

[vthokiefan]

Originally Posted by stiletto7

I can't imagine you don't have any noises. Mine makes all sorts of racket in 3-4 gears with the AFM. I hate the AFM. And I have the extra Resonator still in there. I have to imagine its worse when you take the resonator out! BTW - it only makes the noises if you aren't accelerating hard.

Ok so not sure what AFM stands for here.... I'm a biomedical engineer and do some materials research and AFM to me is "Atomic Force Microscope" which I use on a weekly basis hahaha... Someone care to enlighten me please?

*edit: Never mind found it. I didn't realize it was the same as the DoD feature.

[vthokiefan]

Originally Posted by CyberDan

I get a noise when first starting it up, and driving through the gears, I hear the same sound you're describing. Like rice crispies in the transmission, but it goes away after warmed up... I'm thinking I'll put amsoil or rp in my tranny to see if it helps.

Yep that's the sound exactly.... seems to be most noticable when the engine revs are low (under 2.5K or so) in 2nd-4th. Yeah the last time I drove it I made sure the trans temp was up to running temp before even switching to M mode and could still hear it, although not quite as loud.

It's just a little weird because I don't ever here the noise when in D, but that could be because it's shifting to the next higher gear before the engine RPM's are getting high enough to make it noticable. The only reason I brought this up is cause it kinda sounds like there are little chunks of metal in the transmission getting knocked around... not a good sound on a car that doesn't even have 200 miles on it yet, ya know?! Just wanted to see if anyone else was hearing it... glad to know some others are and that it may be "normal" for the car.