2020+ Drivetrain Noise

Hello,

I have a 2020 4WD Limited and with ~12000 miles and I recently started hearing what sounds like an intermittent bearing noise when I make slight changes to the drivetrain load at highway speeds (small throttle inputs ON/OFF). The noise I am hearing sounds exactly like what is described in T-SB-0074-19, which as written applies only to 2014-19 4Runners.

I visited the dealer this week to have them look at this and after a test drive they acknowledged the noise, however they noted it is normal for 2020+ 4runners and the TSB does not apply (they said they called Toyota and a design change was made post 2019). So, no action taken and the noise is still present.

I plan of continuing to bring this up at future service appointments to see if a new TSB comes out, however I am curious if any other 2020+ owners have been experiencing this?

Jim

 

Are you referring to the front diff TSB?

 

rear diff
https://static.nhtsa.gov/odi/tsbs/2019/MC-10164329-9999.pdf

 

I just started noticing a very faint rear diff whine on mine at interstate speeds, as chance would have it. Mine is an Off-Road with rear locker. About 14,000 miles on the clock.

 

Yes, this is what I was referring to. Rear diff and/or propshaft. For me, it seems to be most noticeable to me around 70mph, where the TSB says 40-60mph, but the scenario described is very similar to what I have going on.

 

Interesting. How do y'all understand the "countermeasure" referenced in the TSB? Are they talking about the proposed fix in Step 3 (installing sound dampening pads under the carpet in the rear hatch)? In other words, the "countermeasure" is installing those pads and if the problem persists then they should move to Step 4 and install those rubber mounts on the rear frame?

Also, does anyone know what the supposed fix was for 4Rs manufactured after MY 2019? Did they just install these sound deadening pads on everything they built after that? If so, this TSB would clearly imply that the problem could persist in MY 2020 and later, requiring the rubber frame mounts.

In any case, given that the "fix" is simply to mask or reduce the vibration, it seems Toyota does not believe this is a problem of reliability, but rather just a nuisance.

That all make sense to you guys?

 

In addition to the pads, for earlier model years it looks like the TSB suggests replacing the diff. For later impacted years, it mentions replacing a propshaft. I assume for MY2020 and later the pads are already there, and maybe I have a prop-shaft issue (unless there was a design change in the propshaft as well)?

This of course assumes I have the same issue as documented in the TSB. for my limited, I have full-time 4WD, so there are lots on things spinning under the vehicle that could be causing the noise. I really can't differentiate in the noise is from the front or back in my case. Just was curious if others have been experiencing something similar.

 

PS I haven't noticed an issue with my 2020 Limited, but it has less than 12K miles on it.

 

Oh yeah I see now that the TSB recommends replacing the Diff or the propellor shaft, depending on whether the truck is pre or post "countermeasure." So now I'm more confused about what the countermeasure is and also more concerned that there's a serious issue here. Toyota wouldn't be replacing entire diffs and shafts unless it was a big problem. Ugh.

 

I assumed the countermeasure was the factory installation of a new real differential design, but I agree it is confusing. Regardless, on my 2010 Limited (traded in at 165k miles), I never had this sound, and it just seemed to start within the last 1000 miles or so on my 2020. If it was "normal" per the dealer, then why did it just show up? I don't think it is normal, and it is really just an annoyance right now.. however it is now a documented issue with the dealer and I'll continue to bring it up moving forward.. maybe the TSB will be revised for 2020+ if enough people have this issue and bring it up.

 

Same thing happening on the tacomas. Very similar TSB fix. 315 pages for you.
https://www.tacomaworld.com/threads/3rd-gen-poll-rear-end-noise-howling-when-feathering-throttle.442341/page-314

 

Follow up: I changed my rear diff oil today with mobil 1 75w90. Took it for a test spin on the interstate, around 20 miles, and so far the diff is quiet. Not hearing the slight whine under light throttle load.

Probably was a bit early, but I have used it under “severe duty”, so not that far off. The oil was grayish, and the plug magnet was slightly mounded with gray metallic sludge.

We’ll see if stays quiet.