[Amsterdam9#]

Hello, I have a 2009 CTS base model with 62,000 miles on it, when it is in automatic mode if I take off fast I hear like a rumbling sound coming from maybe center or rear of the car , if I put it in the sport mode option I do not hear it, any experience out there with this , thanks Rick

 

[Big_kid]

Center drive shaft support bearing maybe ?
You will need to remove the heat shield above the exhaust to inspect.

 

[Amsterdam9#]

THANKS !

 

[CWB]

Center drive shaft support bearing maybe ?
You will need to remove the heat shield above the exhaust to inspect.

Actually I inspected from the rear of the car without removing anything. Put vehicle up on a lift that does NOT support the tires with someone in drivers seat to crank and put in drive. Be very careful that vehicle is not vibrating or shifting when you do this or you will have a new Youtube video of what NOT to do. Look at rear differential and look forward along drive shaft with a light as car gently accelerates and slows. Large vibration of center of driveshaft means you need a part. Good Luck.

 

[Amsterdam9#]

THANK YOU !