[KillerB2SS16]

2016 2SS A8 with around 47k in mileage. I drive the car to and from work 5 days a week, which in total is less than 100mi a week, dont race, never tracked, and have kept the car in peak running condition, with the exception being the trans flush since the car does exhibit the A8 shutter/stall/clunk issue because GM wanted to fight me and charge me Big Bucks to diagnose it.

This metal on metal sound first occurred about a week and a half ago and comes from the rear of the car, from my perspective the left rear. It has slowly and progressively gotten worse since then, going from only doing it after the car has warmed up, to now most of the time when I cruise or coast from 0-40mph with or without the brakes applied.

Chevy wants to charge $230 just to look at the car. I am not in warranty. I purchased the car used with 23k miles on it. I am aware of the TSB and the class action lawsuit for the A8. 1 week prior to the sound, I did change the Thermostat after the fan would start on high when the car first started, issue has since gone away.

In any of your experiences, does this sound fit with the dreaded Torque Converter, or Rear Diff problem caused by the A8? Or is it another issue?

https://youtu.be/wV4c5iER87k

https://youtu.be/1vxDGN7R3w8



(Sorry for the low video quality from my cousins old cellphone)

[Z28GTOSSMike]

First thing I would check are the rear brake pads.

[N Camarolina]

I second checking the brake pads, as that sounds like the warning screech tab tellling you that you have 3mm left and it's time to change them.

You may be able to see them without removing the wheel. You can try using your phone to take a picture of the pad material from the end. Place your phone perpendicular to the rotor, with the camera lens facing the caliper / end of the pad. If the pad material is clearly thinner than the backing plate, the warning screetch tab is likely making contact with the rotor and making that noise.

If brakes are OK, next thing to check might be rear wheel hub/bearings. You can check that yourself with wheel off the ground. You attempt to find any loose "play" in the wheel/tire by grabbing the tire with one hand on each side (9 and 6 o'clock) and apply a forward push from one hand and a reverse pull from the other hand. See if you get any free play when you do that (you shouldn't if the hub bearing is OK). Then try hands at 12 and 6 o'clock and repeat the test.

[ctrlz]

Agree, sounds like wear indicator for brake pads.

[KillerB2SS16]

Thanks for the suggestions. I will be looking at the brake pads here momentarily and fingers are crossed that that is the noise.

[KillerB2SS16]

The best pictures I could take, not much difference between the warning tab and the pad itself. Still seems to screech more when the car has been driven for 5-10mins then it does when its cold.