My 2001 Yukon Denali

[yukondoit]

Welcome to the site. Like everyone said, drop in altitude, HIDs..

 

[RSalander]

Hum is probably from the differential.

I'm guessing the front diffy? If so, how do i check that? Can i fix that myself or do i need a shop to do it?

Thanks.

 

[denalianyone]

You can probably try changing the diffy fluid with royal purple...more than likely it will be a temporary fix. Replacing the unit is your other option.