Bea10xD

Hi I just bought a 2010 Scion xD it's got 97k miles on it, I noticed a grinding sound when driving it and my foot is on the gas pedal. It's a 5 speed manual and it's not bad in 1st or 2nd gear but above that it gets louder. When I shift gears and my foot is on the clutch it goes silent though, it's not the engine bc I can hear that separately. It could be the timing chain or that's just what the engine sounds like. Of course the dealer told me that's just the way it sounds but it is quite loud. Just curious if anyone can clear that up for me maybe