weird noise from under hood or steering wheel?

I have a 94 lumina z34. automatic. their is a weird noise coming from directly in front of the steering wheel underneath the hood. The noise only occurs when the car is moving. the noise sounds kinda like two gears grinding. the noise dosent get louder or faster when i hit the gas. it just stays the same. also when this noise is occuring if i grab the shifter you can feel the vibration of the noise. also when the car is idleing it has a weird whinning noise but when i hit the gas it stops. any help would be great thanks.....