Loud hum
 

I have had a lot of help on this site, so here I go again! Haven't driven my car in a few weeks - rainy weather. Today is sunny so I took the car out. After a few miles, I started to hear a hum which kept getting louder. By the time I got home, it was pretty loud. I have felt like the clutch was starting to slip. Can the two be related? Thanks. BTW, my car is an '11
V8V S with the ss2

The noise is outside of the car and sounds like it's on the right side. Almost like a pump, but not a squeal like a bearing. Water pump? The direction of
the sound can be deceiving, but I left the car running when I got home, and it sounded like the right side.

A pump in the engine compartment? Or towards the rear of the car? A mechanics stethoscope can be helpful.

You have a Vacuum leak for the exhaust bypass, simple to check, remove fuse #22 in the left rear fuse box. (under the carpet in the trunk) yellow 20amp fuse.

After removing fuse #22, how to test?
I recently removed it and got emission service required message. I cleared the fault code and it came back after a week. I put the fuse back, cleared the fault codes and waiting to see if it comes again.

Fuse is for the vacuum pump in the right rear of the car. Removes the power to the pump to keep it from running. Later models the fuse is a 5amp in #15 slot. you may want to check that.

OK ! I pulled fuse 22 and started the car. Definitely louder at idle. I am going to drive it tomorrow or Wednesday,
when the shop is closed. No hum at the moment.

Thank you, everyone !

What was the final verdict on this? I am having the same issue, removed fuse 15/22 and the sound still is there on startup

No verdict. Life was a lot busier at the time. Since then, I have retired and now I am busier than ever.
Now that you remind me, I will get the car up on the rack before spring and see if I can find the vacuum line.