2021 SR5 4WD Strange Drive Line Noise

Hello All
I recently purchased a 2021 SR5 4X4 Taco from a local Toyota dealer . It is a certified truck that is very nice and clean. 54000 miles on the OD. After owning this for a week I started to notice that when driving between 20-40 mph I could hear what is a whine,howl or droning noise that is drive line related. When I come to a stop on a flat quiet road I can notice it as well. I initially thought it was a wheel bearing and swapped out a front drivers and it did nothing. I then checked and swapped rear diff fluid with correct 75/85 Redline. Nope nothing corrected.(I am a retired electrician that fixed stuff for 35 years) I am beginning to suspect this is a trans noise? It seems to be a bit down shifty at stop signs and the noise is present when coming to a stop/slowing down. I also notice a whine type noise at freeway speeds. I just sold my 2022 SR5 to my son and my previous truck had no noises like this at all. I am taking it to the dealer next week and have little faith they will detect or remedy this noise. The driveline and engine is under warranty until Odometer hits 100,000 miles from Toyota via certified. I maybe getting ahead of myself but If they cannot ID and fix should I dump this thing or ignore it and wait for it to fail ? It is there at all times but not super loud. Almost like a failed bearing. I did put the truck on 4 jack stands and could detect it clear as day when running in the air between 20-40 mph. But cannot detect where?? The dealer service manager is doing a ride along for me to explain my issues. Anyone else have this issue with the droning whine. I should note that when I turn it off and glide under no engine power the noise is not present . Any shared stories would be a great help. Thanks to all.

 

It's a know issue. There are a lot of posts on TW about the noise. I call my truck whistling dixie somedays! I hear the noise at various speeds and after reading many posts about it here I just turn up the radio and don't let it concern me...

Congrats on the new to you truck!!

 

Differential noise known issue . Mine has been doing it for years . It’s just a noise . Have heard some get a differential swap under warranty . Then the noise returns . You can have dealer inspect it but more than likely they will call it normal .

 

My 2021 TRDOR makes the same howling sound from the rear diff. I just ignore the sound

 

Thanks folks. I hate to be paranoid but found it odd that my exact same truck that I sold to my son is dead quiet. Its my nature to diagnose and stuff out. 33 years as a service tech and installer does not go away /I never put faith in warranties as well. The Toyota Certified does not cover fluids so that is why I did the diff. The front bearing was so easy it was not worth the hassle of going to the dealer and paying the 100 dollar fee.(I bought a good bearing as well). I appreciate the input.

 

I have the 2021 V6 4WD (SR5) and haven't noticed this on mine. Granted I only have like 18,000 miles on it but
so far it's as smooth and as a babies behind and quiet as a house mouse.... well as quiet as I'd ever expect it to be.

 

My 2019 has a faint rear diff whine in those same speeds, I can reproduce every time by feathering the throttle, it seems to do it when there is no load (engine braking or accelerating). My GF's 2018 4R is the same, but a higher speed. As mentioned already, this seems to be common.

 

It is a very quiet whine . Only at certain speeds 20-40 mph At first I was thinking rear diff pinion bearing. But when I glide it and kill the ignition it goes silent . Not sure because no load or the trans is not working ? My sons 22 SR5 with 40,000 on the OD does not not make any noise. I wonder if dealer is going to say lets change the trans fluid? The labor is covered. The trans fluid is not . Oh yeah trans fluid 100 dollars a quart guessing ? lol
Thanks for your thoughts

 

You said you notice it when you come to a stop? As in you hear it when you are stopped?