When I use reverse in my 4runner there is like a very light scraping almost squeaking sound it makes. If I go faster, it speeds up. It almost sounds like a disc brake dust sheild would sound if it was hitting the rotor. Checked those, not it. It sounds like it's coming from the rear of center of the vehicle underneath. The U-joints have no slop in them whatsoever and I grease them about once a month. The differential fluid has been changed and topped off in the last two weeks and it leaks none. This sound will hang around for a week or two or three then go away for a month then come back. It seems like every time I take it in deep water or thick mud it goes away for a couple weeks. I had a mud bog two weeks ago and it wasn't making the sound afterwards. Cleaned it up and I've been driving it to school every day and it started making the noise a few days ago. Please give me some insight. I've been dealing with this noise on and off for like a year. It's embarrassing. Occassionally it does it a little bit in first at slow speeds two. But not usually as bad.

 

after the mud bog, did you drain the fluids?

 

I'm willing to bet it's your U-joints...

Reason I say that it from recent experience. Just because they have no slop doen't mean their not bad.

I was experiencing the same thing about 3 weeks ago; squeeking in reverse, sometimes in forward, but it was only really noticable at low speeds. Whent out to the woods and through about 2 1/2 feet of water, enough to put the drive line under water, and the noise stopped for a week, then it came back. Reached underneath to try and move the drive shaft around, and it was solid.

I decided to go ahead and do my U-joints, and sure enough one of the caps on the rear joint was completely dry and begining to rust!

Changed em both, now the noise is gone completely!

 

Why don't you lie down behind the truck and have someone back up. That might help locate the problem.






^^For Abecedian and other's sake, don't do this, I was only kidding, despite not having a single smiley in the post. For you Abe:

 

damn, matt16... you're becoming violent.

anyhow, like I 'alluded' to... check the diff fluids, trans fluid, etc.

squeaks aren't good, but indicate something is wrong. hopefully, it's just the u-joints, but don't rule out wheel bearings or maybe even caliper sliders.

 

I wrote that the first time serious. I did that with a Camry to find out was the "grumble" in reverse. I forgot to mention that you ought to lie off to the side a bit.

 

how far off to the side? 2-3 feet?

 

We'll ideally not in the path of the tire, that is the only really critical part.

[YOUTUBE]http://www.youtube.com/watch?v=V6KyDtnacDA[/YOUTUBE]

 

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Rolling tires are not dangerous. Its becoming the intermediate object that separates the tire from the roads that is dangerous.

 

and I quote...

 

Yes. I'll replace the u joints

 

^x2...I had the same squeaking/scraping noise...mostly in reverse, and at low speeds...it seemed to come ang go, and I was thinking clutch plate, or throwout, as the u-joints were nice and tight, and recently greased....2 weeks later, I got a nasty vibration at speeds above 40mph...checked it out, and sure enough...the rear u-joint was toast...I replace only that u-joint(i know, I know), and have put 5+k miles on it, without the noise returning.......goodluck!

 

I had a spare rear u joint sitting around in the garage. Im gonna put it on tomorrow morning during auto shop at school and hopefully that will fix it. But it's getting worse. It pretty much squeaks constantly now.

 

Are you sure its not one of your brake shoes dragging?

 

disconnect the driveshaft from the transfer case and put in reverse, you can rule out tranny or transfer case that way. Disconnect driveshaft from transfer case and diff, then roll in reverse down hill. You can rule out rear axle that way. That's what i'd do at least.

 

Jack the rear up off the ground and start the truck up. Put it in R, and see where the noise is coming from before you go start replacing bits.

 

Very good tip, JUST MAKE SURE YOU PUT WHEEL CHUCKS OR BLOCKS ON THE FRONT TIRES! While the tires are rolling backwards, press a little on the brakes, or just pull the parking brake a little; that'll make the noise very obvious if you normally only hear it under a load; this is exactly how I pinpointed it to my U-joints.

 

I've had it running on jacks before and it wouldn't make the noise because there was little or no stress on the u joint with no friction against the tires. I took the rear end of the driveshaft off last night and tried moving the u joint. There was one direction in which I could barely move it with my hand. I replaced it. It is now quiet.

 

score 1 for superbleeder


glad your all fixed up now man, good job!