3rd Gen Poll: Rear End Noise howling when feathering throttle

Just comparing the ride quality in other taco trims. Really don't know if it has any bearing to the howling owners are hearing?

 

Damn dude, you owned 4 2019s?!

 

ya that was an indecisive year for sure, the first one was bought in 2018 though and last one late 2019 lol

 

gotcha

 

I wrote my "poison Pen" email to toyota. Again, I'm sure it will be filed in their "G" bin. I further asked that since they were not willing to correct the issue at the dealer, They should pony up a reimbursement if I take it to an outside repair facility. I'll be surprised if I hear back. I did make a few calls and finally was directed to a facility on the north side of Houston. Interesting conversation. He stated that he does repair this issue and has done quite a few of them. He said that the differentials are built / assembled by robots (my understanding, I could be wrong on this. Maybe he was referring to unknowing persons) and that all the parts are simply installed. Nothing is measured/ mic'ed afterward to verify correctness. Improper shims are used because they are suppose to all be the same, resulting in what we have. He disassembles the rear and usually has to change out ring and pinions because of improper wear. rebuilds with new parts. He stated he has had great success with eliminating the whine issue. Sounds great!!! I just need lots of ready cash.
Maybe toyota will own up to their problems.
What I described in the above is repeating what I understood him to say. I could very well have misunderstood on some level. I seem to misunderstand the spouse a lot lately.

 

Sounds like he wants your money. Plenty of older 3rd gens w/100k running around with out grenaded diffs. I dont think Toyota is in the business of destroying Tacoma's reputation with shoty engineering or an inferior part, just think its more of an annoyance than a long term or mechanical issue. Doesnt mean they shouldn't do anything about it but we have yet to see diffs failing because of this "howl".

 

Not worried nor concerned with a failure. It's just extremely annoying when driving longer distances (200+ miles of highway) . Around town, with traffic controls, its not that noticeable. But after a couple of hours behind the wheel on non stop highway, it gets mildly insane. I guess I could just allow my memory to go back to my Grandparents 1948 Plymouth 3 speed and the whirring sound of the drive train. Sort of sounds like that, I guess.

 

I'd be very skeptical of that shop TBH... Toyota quality control is second to none in the industry, and they have tight control over their suppliers.

Not saying this whine couldn't be caused by assembly errors, but I somehow doubt it given the number of years they've been making these things, and the fact that Toyota has been aware of the noise since the TSB came out in 2016.

Just FYI, another reputable gear shop (ECGS) has disassembled these diffs and analyzed them. They concluded that there's nothing particularly wrong with the setup from factory... they believe the issue lies in the gear design and materials chosen by HINO/Toyota. They're built for strength is how they put it. I actually contacted them about this issue, and posted their response upthread.

 

I have a 2020 and it does have a hum also. 2000 miles, decided to check differential oil level.
It was about a half of a inch low. Topped off, will see if this helps any

 

My Harley has a the same exact whine when in 5th gear. Its very common on the HDs (google HD 5th gear whine).... On the HD its not a mechanical defect.. its the way the gears are cut that create the whine...

 

He wants your money. You can find in the factory service manual all of the gear setup specs and available shims that exist in the Toyota inventory to hit those specs. There are even multiple shims and specs for spider to side gear backlash which very few gear shops ever check or adjust.

 

Exactly. Gears whine, especially certain sizes and cuts and most often under light loads. My guess is the gear whine is typical but it's exciting something that is resonating and it got past nvh. A good nvh study could really track this down and while the gears are the source I'm skeptical to say that's where to look for a fix for the in-cab noise.

 

FYI: 85/140 Lucas made no difference. Still screaming

 

Thats somewhat good news in my book as it reinforces the 'its just NVH' theory... I guess we're back to needing mud tires and a lift

 

How bad was the fluid that came out?

 

Fluid looked clear, but for only having a few thousand miles the drain plug was covered in sludge.

 

Well now its: deal with it or tires and a lift to overpower the sound. Unfortunately I really like the way it drives stock except for the harmonic ice pick in my brain between 55 and 60!
I am thinking about going with the Dura tracks but I’ve heard they are very noisy. I just need enough to not hear the sound as much. Any opinions?

 

6000+ posts. Gettin up there.

 

Ear plugs.

 

Has anyone attempted this direction for a repair (verification/correction if needed, of specs) themselves? I'm up for doing the research on what and how, but if this approach accomplishes nothing in the perceived whine, then its a time wasted. I state "time wasted" because it seems that all I've read in these previous posts referencing an attempt to add a magic additive or change gear lubes is a futile effort at best.