Mystery Grind

I have a 2006 4x4 4L Standard 6 that has an infuriating grinding noise. It first came only when turning at lows speeds, but now I notice it almost like a shudder even when going straight. I can’t be sure, but it feels like it’s coming from the front, and is always worse when turning left. It corresponds with wheel rotation and does not occur when turning the wheel while parked.
In hunting down this noise, I’ve replaced the front wheel bearings, front CV axles, Front shocks, and my needle bearing (it was fine) with an ECGS bushing. I’ve drained and flushed my front and rear differentials 3 times each, and I’m not getting any metallic chunks, just maybe a 1/4 tsp of fine residue on the first drain. I’ve read a lot of posts on here which led me to take most of these actions, but never posted, so here it is. Anyone have any suggestions?

 

If this was my issue I would jack up the truck off the ground all 4. Yell at one of my kids to shove on the skinny pedal and start searching for the sound. When I put myself in this scenario I always have a extra jack stands front and rear. You will need to have 4x4 engaged.

 

My next step would be pull of rotor and look for shiny contact points on the backing plates.

 

Did you look at the brake pad squeelers for low pad or a hung up caliper requiring rebuild or replacement? Did you flush the transfer case also? Does it occur in 2wd or only 4wd - if 4wd look at front u-joints also, if always then forget them. Assume no 4wd lights flashing or stuck on.

 

Thanks for the input - I’ve pulled rotors and calipers on both sides multiple times and the backing plates aren’t rubbing. Brakes and calipers are in darn near perfect condition. I did not flush the transfer case - that may be a next step. I like the jack stands idea. I’ll try that today.

 

Update- tried putting it in 4wd on jack stands and letting the wheels turn. It doesn’t make a sound. I tried turning both ways, even in a left turn where it normally sounds like an ice machine. Whatever it is, it won’t do it when the wheels aren’t loaded.

 

At this point, I wouldn't rule out something loose in the suspension. It's not logical but maybe you're getting some vibration through the front suspension and frame that would normally be isolated by a good rubber bushing. Check ball joints, control arm bushings, etc.
This is not likely the culprit but it sounds like you've ruled out the 'usual suspects'.

 

Look at wheel bearings. Had similar experience and had to replace both sides

 

I have a 2017 4x4 that just started with a low grumbly grinding noise with very similar symptoms. No noise when rolling straight, accelerating, braking, etc. The combination of things that make the sound are if you corner at a medium speed (20km/hr) with a tight corner - tight enough to get some G-forces going. I noticed it on lefts but also got it to grumble on a tight right as well. My truck only has ~60,000km (40,000mi) so I am not expecting double wheel bearing replacement at all. My suspension is barely a year old and is a high-end Elka setup and I got the ECGS done at that time. My lift is 1.5-2" so nothing crazy at all. I haven't really started hunting for it but if any one has ay intel I am all ears. I Googled and YouTubed the crap out of this and came up with nothing useful so far. Hoping gurus on TacomaWorld might know.

 

if it has a factory rear locker (not elocker) add the slip additive to rear diff, it will cause all kinds of shudder/pop noises, vibrations etc, the stuff breals down over time or if you changed the gear oil and did not add it its going to cause issues

 

That is a possibility for some trucks but my 2017 does not have the e-locker.

 

I'm with this gent.

 

Replaced both sides at what mileage though? I had other Toyotas that had 400,000km 150,000km and 220,000km and I never did wheel bearings on any of them. The thought of needing wheel bearings at less than 60,000km seems insane to me.

 

that's the point a locker diff has clutches that with out the additive will cause lots of shudder/pop etc when turning. (E LOCKER only locked when applied via switch) the other two options are a LSD or open diff so there is a 50/50 chance you have one or the other, if unsure add the additive because it wont hurt either way
on my truck there is a sticker on the diff that says its a LSD, which means it needs additive

 

E locker doesn't need additive as it doesn't have clutches, it's either engaged or it isn't. The LSD diffs do have clutches but only from 2005-2009ish. After that, the lsd consists of open diffs with brake modulation.

@DarinL don't assume it's not the wheel bearings, actually rule them out. Mechanics stethoscope on the spindle while you spin the hub by hand up on jackstands. Also, double check for play on the drivers side CV axle towards the diff side. In and out is fine, up and down (hood to floor) not so much. I know you said you did the ECGS but still, rule it out

Also, what size tires and wheel specs? Might be some rubbing on suspension components if not stock

 

It's 100% not the wheel and tire combo as I've had 265/70R17 since day one and the grumbling noise is a new phenomenon. Tire rubbing would happen at full crank regardless of speed but my issue only makes noise when cornering tightly and it doesn't need to be full crank, just a tight corner like when turning around in a cul-de-sac. I have the LSD.

 

You don't have the LSD, you have an open diff with simulated lsd

 

Yes - we're saying the same thing differently. My 2017 without the e-locker has Toyota's automatic LSD thing which simulates an LSD if you activate it. It's not the LSD because the LSD function is not on so I'm in open diff mode.

 

I believe I was around 90k miles when they had to be done. Our Land Cruiser is at 230k miles and never had wheel bearing issues

 

Time for an update!
First, thanks to everyone who shared experiences and opinions. Every one was valuable in their own way. Here’s the full story of how I finally solved this issue:
I listen to the “Under the hood show” podcast, and decided to call in with my problem. The host suggested brakes, but stated that if I brought it to their shop, they would use “Chassis Ears” to isolate the noise. I’d never heard of these before, but found one for $100ish on Amazon and gave it a try. BUY ONE!!! Life changing tool. I put 4 mics on all four bearings and drove in a circle in a parking lot, isolating each one. I could distinctly hear grinding coming from my right rear louder than the others. I moved all 4 mics to the rear diff, brake drum, wheel bearing and left bearing (for comparison) and pinpointed the sound to the bearing. I bought a new one from 1A Auto. I was apprehensive about changing it myself, but after a few youtube videos I decided to give it a try. There is a critical tool that you need to pull the rear bearing, in combination with a hydraulic press. There are some knock off tools available, but I followed the advice of one youtuber and emailed the original designer directly. Duane is extremely helpful and will give you a deal if you email him directly and cut out the middleman -
dtb2253x@yahoo.com. Here’s his tool on ebay:
https://www.ebay.com/itm/202909661596

Long story short, don’t forget to remove the snap ring! I blew out a 20 ton press before I remembered to pull it.
The happy ending: New rear wheel bearing, no more noise!