bandman659

Truck: 2000 4Runner SR5 V6 2WD, stock as stock could be (aside from 235/75-15s instead of 225s)
Mileage: 186000

For the last 6 or so months, my wife and I have been hearing this grinding/roaring noise coming from the rear end of her truck. I thought it was tire noise, but the noise starts almost as soon as the truck starts moving and it's pitch is directly tied to vehicle speed. It makes the noise in drive and reverse as well. I've rotated tires around and they're all in good shape and I've also changed the oil in the rear end with some valvoline 80w-90. No dice, still makes the noise. Maybe not quite as loud, but any change is probably just the placebo effect. First thought: axle bearings toasted

Today I finally put the rear end up on jackstands, put it in gear, and listened around with a mechanic's stethoscope. Good news: NOT THE AXLE BEARINGS. Yay, I suppose. It seems to be coming from the front of the rear third. Actually, it seems to be loudest at the center of the driveshaft, but that location doesn't make a damn bit of sense to me, and there's plenty of grinding/roaring noise at the front of the rear third.

My father-in-law and I both think we're down to the pinion bearing being the culprit and the driveshaft acting as kind of a tuning fork for it. I called a dealer to see what they would charge to replace it just as a starting point, and when they said $1350, I started laughing and didn't stop till the guy hung up on me.

So does the pinion bearing sound like a likely culprit for a roaring/grinding noise that starts as soon as the vehicle is in motion and is present on acceleration, deceleration, steady-state, and coasting in neutral that definitely isn't the axle bearings?

Follow-up question: What's an appropriate price for a used third at a boneyard and how can I check if the pinion bearing is stuffed on one without running it?

warpigg

i would say it was the pinion bearing because my moms 4runner had the axle bearing go in it and it was either that or the pinion bearing because it made the roaring sound. and we got two third members from a junk yard where i live for the older yotas(87 4runner) for $200-300 or less each. newer ones i would assume cost around the same for your year because i think there identical or damn near. we were also good freinds with the owner of the yard so that makes a difference.

erixxx68

If it is the pinion bearing, it is better to fix it before it breaks. I had one lock up on me and at that point the rear tires wont roll. I was lucky that it happened just as I left a stop sign and wasn't driving fast, I never had one lock before and the thought of it at 70mph could be scary. Not being able to coast or push it to the road side could also be dangerous at night. My experience was bad because I was blocking traffic on a 2 lane road.

SkidPalace

Maybe this will help:
http://www.4x4now.com/gt0699.htm

Team420

x2 on that!!

I Watched the one in my 93 lock up while my wife was driving it, she was only doing 25mph thank god, and it was a snow covered road... the truck swung around on her, and stopped dead... If she had been going faster, or was on a dry tar road... I could only imagine how bad it could have been

jonnydclark

Same question: What's an appropriate price for a used third at a boneyard and how can I check if the pinion bearing is stuffed on one without running it?

I've been living with noise coming from my rear end for years (ahem, i mean my trucks rear end). I bought my '97 with 143,000 on it and at the time I told the seller the rear end was loud and likely going out. He swore it hadn't change in the 50k he had driven it. I took it home and changed it to synthetic gear oil but the oil coming out looked ok. Nothing has changed since and it has ~180k on the clock. It doesn't really bother me but when I drive my sisters Runner with more miles than mine I realize what it SHOULD sound like. My noise does not seem to be directly related to speed but some combination of speed and torque on the drive shaft (i.e. accellerating or coasting). I would recognize a wheel bearing so I'm pretty sure it is in the diff but haven't gone under it and listened. Should I be worried that it will lock up or would you think it is a different bearing?

jonnydclark

oops... just read the info in that link and it is quite helpful.

JWaldz

iTrader: (1)

I'm dealing with the same problem.. and I'm assuming it's coming from the diff. I have the same symptoms you described. I know it's not an axle seal cus there is no leaking or anything around the hubs and I just changed my rear bearings not too long ago.

I'm upgrading to an e-locker rear axle and swapping the whole rear end of my truck, so I'm hoping it will go away when I do that. However, I'll be using my same axle shafts so If the problem persists I know where to start looking.

To the OP, let us know what the outcome is.

bobtheo

first off that price is way too much for a fix like that, and we had a old chevy 1500 diesel come into our shop and they said they thought it was the bearing where the the lower drive shaft came together on the upper drive shaft. but what happened was the yokes got welded together (not by a welding machine, but through just driving it a long amount of distance without stopping) and we got a price quote on it and they wanted 1500 just for the upper drive shaft.

what im trying to say is, that try going to a regular old shop to get it checked out, and its cheaper, and they wont charge you an arm and a leg for that kind of work (not all of them, i know a couple of em that will charge like a dealer would). and if you need a new drive shaft for it, talk around and you might find shops that will make them for you. best of luck to ya

warpigg

i dont think anywhere on this thread anyone mentioned anything about driveshafts. and we have mostley narrowed it down to being only a couple of things. and what do you mean upper and lower driveshaft? as far as i know there is a front and rear drive shaft and thats it.

bobtheo

ooops must of read it worng, and some wehicles have a drive shaft that can be taken apart into two pieces, mostly on bigger trucks, in other word its got a joint in it so it can flex when it turns. lemme read it again, i only glanced at it anyhow.

edit: when it made a roaring noise did it make any kind of shaking motion, so to say?