new noise when shifting

[skycat]

Hello to all -
I had the Sky in for an oil change and windshield replacement (rock chip expanded to a crack from top to bottom). As soon as I started the car before leaving the dealership, I heard a new noise. It's hard to describe - kind of an airy, slightly hissing sound heard above the engine running. As I drove away and shifted, I heard a kind of sucking air sound when letting out on the clutch between every gear.

I've had my Sky for 14 months, and this is definitely a new noise. I took it back, and the tech thought it might be a dirty air filter. He replaced it; the noise is still there. Bottom line, he couldn't find anything. It doesn't seem to be impairing engine performance, etc., but it bothers me that this has suddenly developed, and curiously after a dealership visit.

I'm going to take it back again, but have been driving a lot without the radio on to see if I can add any more info to the problem. The sound when shifting is sometimes loud enough to hear above a moderate volume on the radio.

Anyone else have this, or have some suggestions as to what it could be?

Thanks!