Read some other posts on whining noises and not sure if this is the same issue?I only notice it when slowing to a stop.Not sure if it is doing it all the time and not just loud enough to hear till slowing.
Hard to say based on your description. For some people a whine might be a growl. IF it is the rear diff coupler, which is described as a "growl" it's covered by an extended warranty, as you may have read in the other threads. Sometimes you just gotta ask the dealer shop, trust them to do the right thing and fix it for free if covered.