Odd noise - Brakes? Gear?

[Phibernaut]

The rear end of my 2002 GT has been making a rr rr rr rr noise and its getting louder. I've been told it behaves like a bad pinion bearing, but it doesn't make the same kind of noise. It sounds similar to a brake pad warning indicator and only appears when I'm on the gas. As soon as I lift my foot the sound goes away. It gets much louder around left turns, and almost disappears around rights (or is it the other way around?).

I replaced the pads thinking that would fix it, and it seemed to for a while until the brake system had fully pressurized. I noticed the inside left pad was significantly more worn than the others. I'm told its not uncommon to have one pad wear worse than another, but it seems logical the pad has something to do with the noise. It definately seems to be coming from that corner of the car. The only thing that makes sense is a bad disc, right? Any help is appreciated.

 

[triggz]

If its the rear end, in my experience it will get significantly louder once you get to 3rd gear. Does the chunk appear wet, or seem to be leaking around the dif. cover? Check the fluid and look on the drainplug- its magnetic so it will have shavings on it. A small amount of fine mud-like grey paste is normal to find. Chunks/pebbles are bad.

It could be that one of your rear calipers is partially siezed too. When you did the brakes, did you have any trouble sliding the calipers apart/together?

The upper slide-pin thing on one of my rear calipers was siezed solid, but the lower one was free, so this made the brakes engage at an angle ultimately making uneven deposits on the rotor and causing rythmic whining and eventually grinding.

 

[Phibernaut]

Odd noise

The caliper piston was difficult to move, but i figured it was just because we were working against the brake system. We used a small square tool made for twisting and shoving the brake piston back. I don't recall the slide pins having any trouble, but it's something I'll look into. Would it still make noise even when I'm off the brake if that were it?

 

[triggz]

Depending on how the pin is seized, it could be partially closed. You said one said wore out faster? Good indicator... the pads should wear out the same.

Look at your tires too. A blown strut or otherwise unbalanced suspension can cause crazy tire wear patterns and odd noises.