2003 Toyota Tundra TRD 4x4 hum/whine issue

Hello everybody,

I have a 2003 Toyota Tundra TRD package. Currently it runs flawlessly in every way but one…

When I engage 4-Hi on our snowy/icey roads here in Alaska everything works properly until I take my foot off the gas. There is a soft whine or humming sound that sounds like high rpms when iyou are shifting down to second or low going down a steep mountain road. This whine happens only when I take my foot off the gas and immediately goes away once I accelerate or shift back into 2wd. This sound does not occur when I am in 4-lo just 4-hi.

The whine doesn’t sound like any metal is grinding and there are no pops or bangs whatsoever just this high-pitched humming. 4-hi still works the way it should and disengages properly.