I have had this problem with my Dodge Ram Laramie for many years now with no resolve. Only have 30K miles on it and like new conditions. I have a strange, infrequent noise that comes from the rear of the truck only when I either first start out or more pronounced when I back up that sounds like a loud horn or rubbing-like noise that will disipate when the vehicle comes up to a higher speed. It does not do it when driving at a sustained speed, only at a low, starting out gear ratio. Been to the dealer many times to no avail and just recently went to a transmission specialist to have the differential fluid changed and inspected and other items checked but to no avail, still makes this strange noise with no apparent pattern or frequency. It does have an anti-spin differential axle with an 3.92 axle ratio, if that makes a difference to anyone.
Don't know where to turn to next, all applied help and info is requested.
Thanks!

 

Welcome to the forum.

Sounds to me like a dragging parking brake inside the rear rotors. They are a small drum brake assembly inside the rear brake rotors.

 

Yup........

 

I never use the parking brake on my vehicle, so I'm really unsure of the answer i received so far. The noise does sound like a loud groan, which definitely can be heard inside and outside the vehicle.
But at this point, I will check out anything and everything!

 

It's also possible that the park brake lining is seperating from the shoe. On my 03 about 10 little dots of glue is what they use to bond the two together.

 

Now I'm not a truck mechanic, but would the parking brake possibly cause this noise I'm hearing even thou I'm not using the parking brake as stated in the previous follow-up threads? Can anyone answer this for me?

 

If the assembly is failing, it could be engaging or partly engaging the e-break even though you've never used it.

 

Finally had a local repair shop investigate my problem noise issue and found badly corroded and rusted rear brake rotors. Replaced with new rotors and new brake pads and there is no noise anymore.
Thanks to this forum and the answers given to my problem, this issue has been resolved only after three plus years seeking answers. Dealership sucked in helping to solve this issue.

 

That's what this forum is here for!

 

Yea my rotors were bad making that stupid noise between 5-20 mph and going in reverse. After switching them out, not a peep.