2008 CTS 4 runs great but under hard acceleration loud machine-gun like sound??

[pastorbill3]

'08 CTS 4 with 97K miles performs beautifully under normal driving conditions, but when going into passing gear or acceleration with some but not extreme pressure, a loud noise like a machine gun sound comes from what sounds like the right underside of the vehicle. It almost sounds like a fast series of backfires. Anyone with any experience like this?? Any ideas what it is?

[cadillacmike68]

You might have a hole in the exhaust system.

[pastorbill3]

It turns out it was the bearing on the drive shaft which unfortunately in 2008 was not removable and replaceable. Had to search country for rare brand new complete driveshaft.

[cadillacmike68]

Well, at least it wasn't something internal in the engine or transmission.

That's why we traded our 2008 CTS4. I didn't want to deal with AWD issues When (not if) something on it went bad.