What could this grinding noise be?

[dawgn86]

Hi folks,

wanted to get some advice and information and to learn a thing or two.

My son's truck: 2008 Nissan Frontier V6 automatic Model SE crew cab with 110k miles. New tires put on in September of this year..rode smooth as silk.

Was taking it this morning for a tire rotation when I begin to hear this grinding / grating noise from the rear coming to stops. First thing I think of is wheel bearing(s) going out. I changed the engine oil yesterday and also check the rear diff..fluid full and clean. It was changed about 15k miles ago. I also then put on a new axle vent from Nissan. I seems ok....no oil leaks around the diff or wheel hubs.

On the rack at NTB, the guy ( know the tech ) and I looked at it and he thinks wheel bearing as well. They quoted $450 to replace both bearings.
My rear end is the C200K. I am assuming, in this process, does the rear axle have to come out, bearings pressed or cut off and new ones, with oil seals pressed back on? While I can do some wrenching, this appears to be beyond my ability.

I took the tire off and looked at the rotor and brake pads. They have about 30k on them..still looked good as well as rotor. You could hear the pad touch the rotor when you turned the hub. Could this be a warped rotor scrubbing on the pad during rotation?

Thanks for any advice.

 

[SirTanon]

If the grinding is only apparent when you're coming to a stop, then it's almost certainly a metal-on-metal situation with the brakes, or perhaps a chunk of contaminant in the pad.

 

[dawgn86]

I couldnt hear or feel it driving down the road...Coasting to a stop is when I heard the noise...I think it may be worth a shot and replacing rotors and pads.

 

[SirTanon]

Did you check the pads on both side of the rotors? Don't forget that disc brakes require both an inboard and outboard pad, and one can be worn much more than the other.

 

[dawgn86]

I did! both seem to be worn evenly...but the area did look kinda of gunked up..wondering if a slide pin could be sticking after braking and keeping a brake pad touching.

 

[maxdustington]

I had a brutal grinding, parked my car and replaced the wheel bearing. The old bearing looked fine and I never had the problem again. I did some other diagnoses and determined that it was the bearing, but I have a feeling it was a rock or something and I regret not taking the pads out of the caliper to inspect. I bought a tool and my car sat for like six weeks while I waited for it.

You can't jump to conclusions when diagnosing cars or anything for that matter. Service the brakes, if the noise persists continue diagnoses.

 

[dawgn86]

Last weekend, I replaced rotors and pads. Still have the noise.

Had trusted shop check and replaced right rear axle bearing. Still have the noise!
My driveshaft has ujoints at transmission (seemed tight). Carrier bearing not much play. Then shaft has spline covered by rubber boot.

What should I check next?

 

[Dinoburner]

Have you tried listening with all four wheels off the ground, then applying brakes gently then releasing.

 

[dawgn86]

Dino. Just the rear wheels