[TallTexan]

When you hear the whine, let of the gas and see if the whine stops. If so, prob diff going out. Sometime it is hard to tell where the sound comming from.

 

[TallTexan]

Remember, differential whine will usually always be at a certain speed, maybe 40-50 or maybe 60-70. Engine rpms mean nothing. Anything with the intake will probably happen in the same rpm range. If you have a diff whine at 45 mph, you can be in overdrive or in 2nd gear and the noise will still be there. A intake whirr or noise will usually occur at the same rpm.