This started after I did my brake lines. They truck sat for about 3 or 4 days and after I got it all done I was backing out of the garage and heard it for the very first time I thought something was rubbing I looked all over and didnt see anything I drove it around to see if it would go away and at the time it was doing it in reverse and up to 10mph in drive I got mad and threw it in reverse and stomped it. Noise went away and never heard it until about a week or 2 ago(a month and a half and never heard it once) after I came back from the beach(truck sat for 8 days or so). I dont know what it could be to only do it in reverse its been raining here and dont feel like doing anything. Any one got any ideas? If it ever stops raining Ill try to get a vid of it.

 

my guess is you probably need to have your rear drums serviced.

 

Wink, good to see you back in action brother.

 

Brakes only have about 4-6,000miles on them but Ill check them out if I have time today.