Hey everyone, been a while since I posted.

Basically, 135K on my 2000 4Runner 4WD. Saturday night (yep, during Halloween), something very strange started occurring. A horrible screeching noise that I thought were the brake pad indicators coming from the front end of my truck. This was fine because I was planning on doing the brakes the next day anyway. Drove home from my brothers, screeching the whole way, then parked it Saturday night. Took it over to my parents the next day, but strangely there was no noise on the way over. Pulled the front apart, but the pads weren't even close to needing replacement. Replaced the rotors anyway as mine were warped, drove around a bit, no noise. Figured no big deal, must have gotten a rock or something in there and it was gone now.

Drove to work today, no noise. Drove around for lunch, no noise. Driving home however, after about 10 minutes on the freeway, horrible noise started. Persisted all the way home. This sparks a memory, in that the noise didn't start until after I had been on the freeway to my brothers on Saturday night either, about 20 odd minutes. Weird.

It sounds horrible, and the noise and frequency are associated with vehicle speed, not engine speed. Once the noise starts, it doesn't stop until I stop the truck, Speed up, noise increases and frequency increases. Slow down, noise quiets and frequency drops. Braking has no affect on the noise either.

Anyway, checked everything again tonight, no leaking u-joints, no CV shaft issues, boots fine. At this point, the only thing I can think is the wheel bearing on one of the sides. I don't remember feeling any play in the wheel when I had it up doing the brakes, but I could have missed something.

I don't know if this is related or not either, but I have been having a "loose" feeling in the front over bumps as well. The steering isn't loose, nothing feels loose, but going over bumps/pot holes the wheel feels loose.

Do these issues point to a wheel bearing going out, or already out? I searched the forums, but nothing really talked about a screeching sound after freeway use. It's weird that if I stay on city streets there is no issue, but freeways cause a noise.

Any ideas?

Thanks,
Nathan

 

Get it out on the freeway, get everything good and hot. Then, drive quickly home, and put it up on jack stands. Spin the wheels and try and figure out where its coming from.

 

Jack your truck up in the front and wiggle the tire top to bottom. If theres any play at all you need wheel bearings.

 

i had a similar screeching sound, but mine was only at low speeds, i did new pads and rotors and it was gone. my old pads were still good, so idk what was causing that horrid noise

 

wheel bearings usually make a loud low rumble or grumble when they are falling apart....

screeching ? sounds like belts or brakes

 

Yes, that's why I though brakes first too. Belts I would understand, but there aren't any belts that are vehicle speed dependent, not engine speed.

I'm hoping today to try DeathCougar's method and hopefully isolate the noise. I don't remember any play in wheel at all when I replaced the rotors this weekend, so I don't know.

Thanks!

 

check to see if the backing plate is to close to the rotor?? either on the top or the bottom. You might also want to check your idler bearing for the belts and the fan bearing, alternator--see if you got wiggle in those little guys. Maybe what you are hearing is one of those.

 

Check your brake wear indicators, they screach when they get close to the disc,

 

One more thing to throw out there is the center support bearing for your driveshaft. I replaced mine about a year ago, and now the squeal is starting again. But mine also makes noise at lower speeds.

 

wheel bearings usually make a growling sound. but still could be. you been through salt water lately? or, could be as simple as a rock stuck someplace and grinding. if you're having trouble isolating the sound, get it hot so it does it continuously, then get someone to drive it in a tight circle around you, like in a parking lot, so you can listen to which side it's coming from (without having to run to keep up with it. you just turn)

a belt that gets hot and starts slipping once it expands could be doing it too, but you'd hear it coincide with the pressing of the gas pedal, y'no?

 

Still at work so I haven't had a chance to check, but sounds very much like the backing plate on the rotor. However, I didn't see anything, and I can't figure out what would cause it to happen only after having driven at freeway speeds. Actually, that part I can't figure out at all.

Thanks again for all the ideas, and I'm really hoping it's not a bearing, I really don't want to replace one. I live in Phoenix, so the truck hasn't even seen water for months, so no salt water or anything.

Thanks again for all the ideas!

Nathan

 

As mentioned, a shot wheel bearing sounds more like a helicopter in your wheel well than a screeching noise. I vote for backing plate as well. Maybe caliper related? Heat causes expansion, which may in turn be causing a caliper piston to "swell" (if you will) and get sticky after sustained use and slowing from higher speeds. Surface road driving = slower speeds and shorter braking distances, possibly not giving the thing a chance to get hot enough to act up, allowing things to stay in/settle back into place. Just a thought.

 

Your point would be valid........IF 4Runners didn't have a one piece driveline without a center support bearing!

 

OK, figured out the problem. I guess I was suffering from bouncing sound waves. Drove next to my dad, listened harder, sounded like it was coming from the rear. Just because it is easy to test, jacked up the rear and put her in gear, and instantly the sound was there. Turns out, it was the front u-joint in the double-cardan (I think that's what it's called). The u-joint is probably shot, but took it down, put some grease in it, and all the u-joints in the shaft, and the noise is gone.

However, I'm thinking there had to be damage to the u-joint, and now it's a matter of time before it gets worse or fails. But, this is way better than a wheel bearing...

Thanks again for everyone's help and ideas.

Nathan