I have a 2006 V8 sport with 128k miles. Yesterday I did a full conversion from factory brakes to 5th gen Powerstop calipers rotors and pads. I borrowed a friends garage and also changed the oil and rotated my tires, including the spare. About 4-5kmiles ago I put cooper AT3s on all 5 rims. When I finished the brake work, I had a 20 min drive home, about 14 miles. The first 5 ish miles I did the break in procedure on a 2 lane country road. Had no issues. No noises. No clicking. Got on the highway and had no issues. I needed the brakes to be bled more, and I was aware of that but I had work in the afternoon and was exhausted after working on the truck all night. My intent was drop it at the neighborhood shop, have them bleed it and then pick it up on the way to work. No problem.

As I’m about to get off the highway I hear what sounds like tire noise on the passenger rear, which is where I rotated the spare to. I was confused but made it off the highway and onto city streets and realized it was a clicking that would increase with speed, again very much coming from passenger rear. Made it to neighborhood shop. No obvious damage but had them look into it.

I picked it up today and they told me that my parking brake had needed to be adjusted which was not allowing the passenger rear to rotate freely. Which sounds odd because I didn’t have any reduction in power and didn’t hear a scraping or grinding, it was a very distinct clicking that increased with speed. Now the worst of it: they told me that They hear a clicking noise coming from the “rear end” as in differential. Which to me, sounds potentially really really bad and expensive as in a pinion gear issue or something. Is it likely that the parking brake on one wheel would cause a serious issue with no immediately obvious sounds to the point the diff will need to get rebuilt? Im going to pick it up in an hour. So I’ll know more soon. And Monday I will probably take it in to get checked by a real shop... just trying to prepare myself. I will keep everyone updated.

If you put 5th Gen rotors on the rear, there's a issue with the rotors centering properly because the hole in the center that goes over the hub of the axle is slightly larger on the 5th Gen rotors and this allow the rotors to be slightly off center, which causes a issue with the parking brake shoes to drag and thusly causes a clicking as the brake shoes flexes and then release.

Some get lucky and the 5th Gen rotor centers up on one or even both if you're very lucky and then the wheel holds it there and you may not get the binding of the shoes but it's just being lucky, for the most part it's best to only use 4th Gen rotors for the rear brakes for this reason, because the hole is of the proper size to perfectly center the rotor.

It's possible that the garage tech is hearing the parking brake clicking and the sound seems to him to be coming from the differential instead, I can't imagine the brakes even of they were locked up causing something to break in the differential.

Huh that’s interesting. I hope that’s what it is. I drove it home and that click I would now call a clunk. It’s hard to tell where it’s coming from. That’s odd about the 5th gen rotors because I did quite a bit of research on it and hadn’t heard about them being off center. I’ll look into it. That would be a bummer because it has 5th gen rotors on there now as well. It sounded like they adjusted the parking brake so it would clear but honestly this shop has not been trustworthy for much complicated stuff. But it did sound like they rotated the tires and that the clunking was coming from the axle. I’ll wait till Monday and take it in for a second opinion- I’ll take it in somewhere that does diff work if that’s what it is. Otherwise I guess I’ll be ordering all new rear rotors and calipers again. Wife will kill me lol

You can still use the 5th Gen calipers and pads with the rear 4th Gen rotors.

Well that’s a relief. So best case I need 4th gen rotors. Worst case they’re right about the diff. Will check in on Monday.

You have one other possible option, if you can somehow make a sleeve/shim to get the 5th Gen rotors to truly center up they will work fine, so far I haven't read of anyone doing that but it is an option, but the shim/sleeve would have the be rather thin, if you can get them to center properly once the wheel is install they can't move off center.

Just for reference the hub bore difference is...

(5th Gens) Center Hole Diameter 107.95 MM
(4th Gens) Center Hole Diameter 106.17 MM

The difference is 1.78 MM, so the shim/sleeve would have to be half of that... 0.89mm, which is a tiny, tiny bit bigger than 1/32".

Well, I took it to the diff shop and they said it sounds like the parking brake and offered to disconnect it for me if I dont use it much. I said that’s fine to leave and I have placed an order for 4th gen rear rotors. Should be hear Thursday. Hopefully shouldn’t have any damage or need to repair the parking brake but I guess Ill see when I get in there. Thanks for your help.