i have 4 wheel drive. once i start driving at around 40-50 MPH, i start to hear a "wirrrrr" sound coming from the passenger side. it is not a loud noise, just a light hum. this noise happens when i am in 2 wheel HI, NOT 4 wheel drive. i cannot tell if it is from the front or rear. the car drives fine, i do not feel any difference in the ride quality. just this noise. i was curious if the front passenger wheel is stuck in 4 wheel drive, and the front drivers side wheel is NOT stuck in wheel drive. is there a way to test this? thanks