Need some help - Rotational scraping sound coming from rear end

Hey everyone, hoping anyone can help me out with this noise that just started... So I have a 2011 DCSB TRD Off Road truck, automatic, with an OME lift (885s in the front, dakars in the rear). The lift has been on for 25k or so miles and I don't have shims (didn't even know about them until I started researching this problem).

Recently I noticed a noise coming from toward the back of the truck, almost a sort of scraping noise that sounds like it happens when something rotates...gets faster (sounds like a clicking sound) and slower (sounds like a scraping sound) as I speed up or slow down. It's not constant, but like pulsating. It only really seems to be present when I am giving very little gas or else have let off and am coasting. When I am really accelerating it doesn't seem to be present (that I can hear). Braking doesn't seem to effect the noise either. It's also strange, sometimes it happens and other times not. In the mornings it doesn't seem to be present (cold?), but in the afternoon or when it's warmed up some is when I feel like it starts.

Initially I thought maybe I had something caught under the truck or a bent heat shield and it was scraping against the driveshaft but that doesn't seem to be the case. So I started with some easy things...I lubed all the U joints again, they were due but I didn't think that was the culprit, and sure enough that didn't fix it. Last night I changed the rear diff fluid, knew it was overdue but it wasn't too terrible. That also didn't fix the sound. So now here I am...I've done quite a bit of research here and other forums (TTORA) and general googling but it doesn't seem like the symptoms are quite the same as some of the other posts I've found.

So my next step is to jack up the rear of the truck after it's good and warm, put it in gear, and see if I can figure out where exactly the noise coming from. I have a sneaking suspicion it's the carrier bearing since that is something that actually rotates as opposed to a U joint. I guess it could be any number of things though...pinion bearing, rack and pinion (hope it's not this), maybe a U joint although, again, that seems unlikely.

Does anyone have any idea what may be going on or any experience with this? Thanks so much for the help!

Edit for more details

 

As you have done, I Always try the simple stuff first. When did you do you rear brakes last serviced?? It this point I'll pull the 2 rear wheels off and check the brakes / e brake cables and parts. It could be;
Slightly dragging brake.
Dropped hold in hardware/clips in the drum.
Shoes to drum worn off parallel to the axle center line.
Rock or foreign matter got in the drum ???

From what you described it does not sound like a bearing ....

 

I'd definitely pop open your brake drums before trying anything else.

Also, I've read that the e-brake self-adjusts when the truck is put in reverse...put truck in park, apply e-brake, put truck in reverse with e-brake applied. Don't touch the regular brake pedal.

Not positive how true it is, however this method DID save me from a seized parking brake about 2 weeks ago...

 

Hmm...those are really good points. I've had a cold lately so smelling anything has been pretty non-existent, but I keep THINKING I smell something strange after getting out and running the truck for a while...parking brake or something in a drum would make total sense. Thanks for the replies, have a new path to head down!

 

On my Taco, the Rear brakes self adjust when you apply the parking brake.

 

Check your universal joints on the driveshaft.

 

sounds like driveshaft carrier bearing,give driveshaft a tug up and down next to said bearing.

 

It's been nice out so I've been riding the motorcycle, after getting super irritated yesterday (when I was driving the truck again and it was making that noise), I put the rear end up on jack stands, let the wheels spin, and got under there. Safety first, I know Turns out, a piece of the steel shield or whatever that goes around the gas tank somehow got bent out and was SLIGHTLY touching the driveshaft. I have no idea how I missed this in the other half dozen times I crawled under there looking for the problem...but that was the culprit. I guess it was good, made me stop being lazy and change the rear diff fluid and re-lube all the u joints. Thanks everyone for the replies, awesome community here.

 

Thread revival but this helped a lot. Same thing was happening to me but I couldn’t tell where. Didn’t have enough time to really look though. Then I read this and went under today and it was the same. You can see the ring around the shaft where it was scraping. Thanks! Greased up the u joints while I was at it too.