Trans problem? knock.
 

Just started doing it this morning. When you start the car, it idles rock steady at something around 700. As soon as you put it in gear, while still sitting there, the idle speed goes down to like 500 and the tranny makes a very faint knock. If I brake torque it back up to 700 the knock goes away. The car has no check lights and it runs great. One other concern of mine is that when it downshifts, it is not 100% smooth. Has a very slight kick down feel. I have a feeling its the stall converter :( we just bought the car a couple weeks ago.

I just noticed when the AC is on the revs dont go as low, and it doesnt make that noise. Also, it only seems to have a really firm shift from 1 to 2 and vice versa. Im going to bring it in to get the fluid flushed to see if that helps.

Is this a , er...CVT?

Automatic 5spd.