NEW TSB, Whine Noise From Rear of Vehicle

Just a thought and forgive me if has been mentioned but have any of the forum member with the noise change out the diff oil? The reason I ask is because when I checked my diff when the truck only had only approx 10k on it the real diff oil was very dark and the drain plug had quick a bit of debris on it. Front diff was the same. I change the diff oils and the oil is still clean after another 10k. My thinking is maybe the contaminated oil is causing accelerated wear which results in a pinion ring gear noise.

My diff on my '18 is as quiet as a mouse and pull a 5K trailer

 

I think the results are mixed. I read somewhere on here that a guy used AMSOIL Severe Gear and it made the noise go away whereas others say it didn’t help.

 

But it's possible the damage could have already have been done when the oil is changed.

 

That is also true but then you have guys like @nDub that got new rear diffs that were worse than the first one. I really wish we could solve this riddle. Before I LL mine I may try the fluid change. It won’t affect anything because it’s really a maintenance item that I’m choosing to do a little early.

 

If center section was changed and the noise didn't go away its either the resonance sound or the rear axle bearing. I would run it up to speed on the hoist and use a stethoscope to check the axle bearings. If the bearings are OK apply the TSB and everything should be fine. It really is a simple process of elimination.

 

The TSB at first made mine mostly better. It actually narrowed the speed range to about 57-59. Now a few thousand miles later and the noise is worse than ever and present at 3 broad speed ranges.

 

Are you still under warranty? Have the rear axle diaged ar the the dealership. Have them run the truck on the hoist and stethoscope it to determain where the nose is. Generally wheel bearing noise can be heard all the time and gets louder with speed. Ring and pinion noise will gear louder ar certain speed and will again be louder ar double the speed. So at 25mph its loudest then at 50mph its loudest again. Also there will be a noticeable difference in noise under acceleration and deceleration.

 

I just got it back yesterday. The dealer confirmed the noise but they have clearly been muzzled by corporate. My service advisor seemed very genuine and told me this is literally the first one she has had with this issue yet corporate oddly said that they now consider this to be a normal characteristic of the vehicle. I think they wanted to drop a diff in but corporate TA said no. Normal characteristic of the vehicle is such a loser first line argument of almost every manufacturer, but they have now picked their poison.

 

Do you have any seepage around the rear diff bolts?

 

So where did the tech say the noise was coming from? Do you have a constant noise that increases with speed or does the noise change under deceleration and acceleration?

 

The tech wasn’t on duty when I picked it up. When I feather the throttle the noise is present but I’ve now noticed that it’s present at certain speeds no matter what.

 

None.

 

This is so weird. How does Toyota pass a design flaw in the DNA of this truck from one generation to another, even though the engine and transmission is completely different?

That takes talent.

This is starting to sound like a manufacturing or build issue. If you are lucky enough to have a truck that has the correctly built parts, and it was put togethor correctly, no issues.

If you weren’t lucky, the truck turns into a tuning fork.

And to make matters worse, you can’t tell if it is afflicted in the first 50 miles and thus your extended test drives.

 

Amen.

 

And to make matters even worse... Toyota is sending people home with near-new trucks that sound like they have a kazoo under them and telling people "sorry, you're stuck with the truck and we won't be helping you now or when it comes time to sell or trade. Good luck with prospective buyers".

They're essentially stealing $$ from their customers. Abhorred.

Fix this issue, Toyota. PLEASE.

 

If the dealership you where at phones TAS to help diag the issue and TAS decided it's a normal noise the dealerships won't be able to proceed with the repair beacause they won't get paid. Sometimes the TAS experience isn't as good as you expect and some of the suggested repairs are comical. I would suggest a call to Toyota corporate and explain to them you have had the TSB done and the noise still persists. Tell them that the dealership said this is a normal noise. If it's normal then why don't the other new Tacomas you test drove make the noise? Sometimes a call to corporate can get the ball rolling again.

If all that doesn't work pursue the lemon law to have the truck replaced.

If you haven't guessed I'm a Toyota tech and to be honest this is not a common problem. All the Tacomas we have sold at the dealership since 2016 not one has had the diff changed out due to noise.

 

I was going to reply to your earlier post, but I am definitely gonna do it now.

My opinion of the service advisors (1st tier helpdesk) isn’t very high. I also lack confidence in the actual folks in the trenches behind the wall.

What can you say that will change my opinion of dealer service centers?

I’m probably 1800 miles south of you. No offense, but I have never felt a dealer service center has my best interests in their heart. It’s more like they only push you through their quick service process 3 yrs/36k miles. After that, bring your Astroglide.

I have zero confidence they could ascertain root cause on the problems reported here. Hell, corporate can’t even do it.

 

Yes, I kind of gathered you were a tech. I have corporate involved. I really appreciate the help. The dealer made it clear they won’t get paid if they try to repair it.

 

Which is clearly the problem. There is a huge disconnect between the franchisee service center, and the corporate asshats.

I really wish their HQ wasn’t in my state. They haven’t done jack since moving here.

 

It all depends on the dealership. The dealership is an independant business and they are there to make money. Unfortunately most dealerships ( Ford, GM, Chysler and Toyota) are there to vacuum as much money out of your pockets they can. Find a dealership with the right attitude with the customer in mind, they are still out there. As far as techs go most are very talented and well trained but the customer doesn't see that and only get as far as the adviser and service manager. Techs hands a pretty much tied by the service manager and do as told if they want to keep their job.