Can anyone give me advice or insight on my problem. i have a 2001 s80 and when i hit the gas the car starts to make a grinding noise and starts to shake only when i push the gas pedal and once i let off the problem stops. im not loosing any power and my transmission is smooth and doesnt hesitate. but i have no clue why its doing this. it also gets worse if my car is going over a bump or up a hill but like i said even in both those cases if i step off the gas the problem stops. does anyone have any ideas/thoughts/opinions?