I have a 1998 Toyota 4runner 4WD LTD and I have noticed a humming noise that seems to be coming from the rear of the car. I hear it only when I press on the gas pedal, but if I am coasting I dont hear it????
The other thing is that if I put it in 4WD then I hear it when I am accelerating and if I am coasting. What could that be, it is annoying. I just had the transmission and differential flushed and filled???

Thanks
ruvt4runner98