2003fish

Hello all. I'm having this strange grinding noise I can't seem to find. What makes it challenging is that it doesn't always do it, so you can't predict when to troubleshoot it. What's happening is when you brake, as the car is almost stopped you hear this loud grinding noise, and you can pretty much feel it too. And you can keep making it do it as long as you keep going straight, but if you turn the wheels from going around a corner or something, it can make it stop then it won't do it again. Until the next random time that it does, and it can go days until it happens again. Also, which I'm sure is related, is you can feel a vibration at highway speeds, but it's definitely worse at about 75-80 and up.

I had replaced both driveshafts about 1.5 years ago, so I thought maybe they were junk so I warranty claimed them with Rock Auto and got new ones again thinking that may be the problem, maybe at least for the vibration, but wouldn't make sense for the grinding noise. But it did not change anything.

The only other logical choice could be a wheel bearing, so I jacked it up and ran it in gear and listened to both hubs with a stethoscope, but they sure seemed quiet. Even without them not having a load on them, if they were bad I'd expect there to be some scraping noise, but nothing.

I did put the stethoscope on the center bearing housing for the half shaft, and that did sound like it was scraping a bit. But I'm not sure how much of that is supposed to sound like that, and there's also potential engine noise on there too. I just now realized I never listened to it with the engine running and wheels stopped, just with the wheels spinning. Darn it. I guess I can go back and do that. But, what are the odds that that bearing could be causing such a loud grinding noise? One thing I thought was interesting, and not sure if this means anything, but when I replaced that drive shaft I forgot about that set bolt that's supposed to hold that bearing in the housing, yet the shaft slid right out, which tells me that the set bolt isn't really doing anything. Or, maybe that's how it's supposed to be? Dunno. But also, the replacement driveshaft had a new bearing on it already, so it's a new bearing that's in that housing. And, it's making the exact same noise and vibration as with the old shaft, so no difference between the two tells me that the bearing wasn't the problem.

But that housing does have some noise, so I'm wondering if the housing itself is bad? Didn't seem like there was anything wrong with it when I had the shaft out, but I can't think of any other reason there'd be loud bearing noise from that.

The brakes are pretty new, and since the grinding comes and goes, and there's a vibration, so I'm ruling out the brakes being the problem. The only other thing could be the transmission differential carrier bearings, but I put the stethoscope on that too and they sounded pretty quiet. So, I'm kind of stumped and don't want to start just throwing parts at it blindly. I'd appreciate it if anyone had ideas or could help me figure this out!

Thanks

LeX2K

Could it be something as simple as the dust plate/splash shield rubbing on the rotor? FYI there is a rubber plug that goes on the end of the bolt in the carrier bearing assembly easy to lose.

2003fish

Thanks for the reply. I feel like if it were something rubbing like that, it would be more of a scraping noise. This is a legit grinding, like when it happens you're like, whoa, what was that! I wasn't aware of the rubber cap for that bolt. I'm guessing it's stuck up in the housing though, because there's something in there that doesn't look like the outer housing of that bearing. But at the same time that bearing came right out of that housing, so maybe it's not in there. That's something that maybe I should check.

Thanks

LeX2K

Any chance it's ABS kicking in when it shouldn't?

2003fish

I get what you're thinking, but I'm not feeling anything in the brake pedal that would feel like ABS. Normally that thing growls and pulsates at you when it's doing it. Thanks for continuing to try to come up with things though! I can tell ya, I'm stumped too!

Thanks!