Slight Grinding Noise

In my car there seems to be a slight grinding noise maybe comming from the trannsmision. If you aren't pressing the gas its not there its only there if you are lightly pressing down on the gas pedal. It is a very faint metal on metal sound but goes away after you start pushing the gas down more. Could this be low tranny fluid? Another thing I have noticed is to maintain speed the tach has to be a 2,000 rpm's. Thats for 40-50mph (thats all the roads I drive on). Any ideas

Is it an auto or manual? How many miles are on the transmission? When you take your foot off the gas does the car start slowing down fast?

1- Manual Tranny
2- I am not sure exactly how many miles are on the tranny, the car has close to 196,000
3- It does slow down fast when you take your foot off the pedal. It slows down about 5mph every 2 seconds or so

With 196,000 miles, (which is pretty amazing actually honda eat your heart out) I would attribute it to wear. About the slowing down I would say that's probably normal slow down, manuals tend to slow down faster when you take your foot off the gas since the drive train is still connected to the engine so the RPMs have to match. Not exactly sure what the noise could be from, definately check the fluid, make sure the transmission is warm and the car is on level ground and running when you check it too.