I've noticed a very subtle "whistling" sound when I lift my foot off the gas. It only happens at highway speeds and disappears after drag drops the speed by 10-20 mph. The Jeep is new (automatic transmission) and was regeared at 500 miles, but I didn't hear the sound previously. It is so subtle that I need to have the radio and fan off to hear it. The shop says that all regears tend to make that subtle sound. Is this true? Anything to worry about?

 

So you mean you heard the sound after regearing? Cause I just got regear mine and no noise at all bit I'm still in breaking period.

 

It all depends on how the pattern was set when the ring and pinion were pre-loaded.

Is it a "whistling" or more of a "whining"/"howl".

A light howl is usually ok when you are coasting/let off the throttle.

You should be ok but if it starts screaming or picks up in pitch (and under a light tip in throttle), it will die a horrid death shortly.