Rear End Grinding that ISN'T Wheel Bearing

Hi guys, hopefully someone can point me in the right direction:

My dealership was 100% confident (their words) that the grinding noise coming from the drivers side rear on left hand turns was the rear left wheel bearing going bad. Turns out it wasn't. I just had a private shop change it out with genuine Toyota parts, and the noise is just as loud as it ever was. The mechanic said he doubted the wheel bearing was bad when he was removing it. But it's all done now and it cost me $1,000 and the grinding issue is still present.

What else could it be? Mechanic said the axle shaft looked fine. Everything else looked fine. The grinding sounds like a knife sharpening on a stone wheel . . . . a smooth grinding, not a rock tumbler like diffs after they lose teeth. I don't have enough money to chase this issue down. Any ideas what could be going on? Only on left turns under acceleration.

Its a 2018 V6 4x4 SR5 AC by the way.

Thank you!

UPDATE: it ended up being that my Krown rust proofing has been warping the plastic fender liners, and one of them was making contact with the tire in certain situations. It was LOUD. Never would’ve considered rubbing as the culprit.

 

Your mechanic didn’t take the time to diagnose it? Sure it’s coming from the rear? Is at all speeds when turning left?

 

Are you running stock wheels? What happens when in reverse?

 

spit balling here with limited info, but have you checked your brake shoes and drum?

 

the Toyota dealer diagnosed it. But they want $200 / hr for labor. Which is more than Neurologists earn so they can eff off. A trusted and talented private mechanic took my word for it that Toyota was 100% confident in the diagnosis of the issue being a bad wheel bearing. Yes, it’s coming from the rear. It occurs when there’s pull against the inside of the rear wheel, so left turns at city speeds, but NOT at all at highways speeds.

 

I’ll double check in the morning, but I don’t believe it occurs in reverse. It’s when turning left at city speeds. When there’s pull against the inside of the rear drivers wheel.

 

allegedly, the Toyota dealer did and they’re at 3 mil, which for Tacoma rear brake shoes is plenty for another 25-50k miles, they said there’s some 200K mile trucks on the original shoes with lots of life left.

but honestly, in my uneducated opinion, I am leaning toward something weird with the rear brake. Maybe something stuck inside it? Private mechanic said the rear axle and diff etc are all fine.

 

That I get. What I meant was after he installed the bearing for you and the issue still was there. Did he not try and diagnose for you?

 

I had a similar issue on my 1st gen and it was the edge of the backing plate rubbing on the rust build up on the rear drum. Is there a lot of rust back there?

 

That one made my morning.

 

Oh, gotcha. No, I didn’t give him the chance. They were closing and I needed to get home for a web meeting. I just drove off and noticed the noise was still present about 10 miles down the road.

 

I'd take it back to that shop, not to complain, but to simply have them look further into it. I'm sure they'd be willing to help you out and give you a decent price on any additional work since you already have made contact with them. You might just need to take one of the guys there on a ride to show them the noise.

 

Issue solved by private mechanic. Maguire Toyota is terrible. I’ll never go back. This is my Google review for them:

Maguire Toyota service is either incompetent beyond belief or they are scammers. I’ll explain:

• Grinding noise coming from the back of my Tacoma. Only at low speed, only when turning left on an incline. Grinding doesn’t change pitch at different speeds. Strange.
• Maguire says it’s a bad drivers rear wheel bearing. They want $1500.
• Took their diagnosis to a very experienced private mechanic, paid $980 for the same work, genuine Toyota parts.
• Grinding noise still happening.
• Maguire takes another look at it. Finds fluid dripping from the bearing area. “It’s leaking gear oil . . . the other mechanic installed the bearing incorrectly.”
• I go to leave. “ALERT: Brake system fault”. They pull it back into the shop and tell me the brake line on the drivers rear wheel was cross-threaded onto the cylinder. It wasn’t gear oil, it was brake fluid leaking.
• “Well, anyway, we still believe the wheel bearing was incorrectly installed”. They want $550 to replace the cross-threaded parts of my brakes.
• Nope. I drive it to the private mechanic and let him know what Maguire believes is the issue(s).
• Private mechanic finds no cross threading on the brake lines / cylinder, but confirmed the leak. It was a small bit of crud on the threads, which he cleaned off with a rag. Voila! No more brake fluid leaks. Again, Maguire wanted to replace parts for $550.
• Private mechanic conducts a diagnosis of the grinding noise. Cannot find anything wrong with either rear wheel bearing. Nothing wrong with the axle or the diff. Or driveshaft. Nothing is broken. Strange.
• Happens to notice that the plastic fender liner warped and is hanging about 2 inches from the tire. Zip-ties it back.
• Grinding noise gone.
• Maguire diagnosed this noise TWICE as a bad wheel bearing. It was a warped fender liner sagging / rubbing.
• Maguire claimed brake parts needed to be replaced due to being cross-threaded. It was a bit of sand / crud on the threads that caused it to leak, and was perfectly fine after being wiped off with a rag and re-tightened.
• In total, I am out about $1,200, for replacing a perfectly good wheel bearing, and Maguire’s diagnostic fee of $200. For a plastic fender liner rubbing on a tire.
• How embarrassing for them. “We confirmed the wheel bearing was bad with a special stethoscope!” “Our Toyota master tech has 20+ years of experience!”
• Maguire Toyota service is either incompetent beyond belief or they are scammers. I cannot recommend more fervently that you avoid this dealership.
• Merry Christmas!