Faint whistle or whine while accelerating

Hi all,

I've seen a few posts about different problems while accelerating but wanted to get some insight from you guys.

I have a 2020 TRD OR with 7,500 miles. I'm the original owner and it has no mods. Over the last month or so I've started to notice a very faint whistling or whining sound when accelerating. I mostly notice it between 50 and 60mph while the accelerator is down. The sound immediately stops when lifting off the gas, so I don't think it's just wind noise.

It's difficult to pinpoint the exact location, but it sounds like it's coming from the rear of the truck.

I took it into the dealership today, but they couldn't identify a specific problem. The service rep said the tech had heard a very faint sound, but couldn't pinpoint where it was. He said it could be early stage rear differential problems, but advised me to keep driving it until it gets worse. However, the video and paperwork he provided stated they did not hear any abnormal sound - contradictory to what he told me as I was leaving.

Anyway, I wanted to see if anyone else has ran into this situation and has any advice. I'm not too worried about my day-to-day as I don't drive that often since I work from home. But I was planning a 1,200 mile road trip and I'm not so confident in driving this now. Seems like my only option is to wait it out and see if it gets worse.

 

Mine has a whine while the A/C compressor is on, Almost sounds like the rear diff. Toyota said it's normal(as usual) Something to do with the orifice tube.

 

Mine does it too, between 40 and 60 mph, but with my foot off the gas.

 

Relatively speaking to every other vehicle I've owned (and every vehicle I've ever rode in for that matter), the rear diff whine isn't "normal" but it is "common" in Tacomas. Plenty of people have had the same issue brought up before. Your dealer will either tell you/do:
A) No issue found, bring back if it gets worse
B) Use chassis ears and hear a faint noise, advise to bring back if it gets worse
C) Apply sound deadening to the rear diff (however they do that?)
I had the dealer tell me they couldn't find the issue and that it was most likely the truck still being broken in. After about 10k miles, I brought it back for the same issue and the tech used chassis ears with the master tech in the passenger seat and they took it for a spin on the freeway. They admitted that they heard the noise coming from the truck, but that it wasn't a cause for concern as they took another Tacoma on the lot for a test drive and it did the same thing; I also tagged along and heard it in the borrowed truck. They then advised to take it back in if it gets worse or the truck spontaneously explodes.
20k miles in and I still hear it on the freeway, but it hasn't gotten any louder or changed any driving dynamics. I've seen some posts where the dealer applied sound deadening material to the rear diff, but the sound was still audible at times (albeit quieter) and I feel like the material will probably do more harm than good down the road.

TLDR: Common complaint. Enjoy your road trip.

 

Mine is quiet so I’m just spit-ballin’ here.....but has anyone tried putting a litre or quart of a thick oil treatment like Lucas in a noisy diff to see if that makes a difference?

 

Automatic?
Light, medium or heavy acceleration?
Less pronounced in S4 vs D?

 

Mine does it at 49mph when I feather the throttle let off the gas and goes away . Mine is a manual .. been like that for awhile now . No clue what it is . Let me know if u figure out what it is . I hate going to the dealer for them to waste my time and tell me it’s normal . Or start tearing stuff down and end up making things worse and creating new problems . I have had the noise for months and haven’t notice any problems with the truck . Might just be a harmonic noise from the exhaust .is my best guess .

 

My truck has had a whiny (lawl) diff since I took it home at 85 miles. Occurs around 50-90mph and stops when you let off the throttle. From all the post around here it's pretty much deemed a "3rd gen thing." Some have been told it's normal, some have gotten a new diff only to discover it does the same thing. Tacoma's are quirky trucks. Around 3600 miles on my 2021 OR at the moment. I may or may not mention it during my first service.

 

https://www.youtube.com/watch?v=a5JsSGJCY9g

I managed to catch some dash cam footage with my version of the whining noise. At 15s, is that similar to what everyone else is hearing? I was on the gas at that instant, but I've also heard it when coasting, and at a variety of speeds.

 

Could be this

 

Great questions! I would say all of the above. Medium most of the time, but when I hear the sound I sometimes let off and feather it lightly to hear it come back. Not sure if I really tested it with heavy acceleration as the engine noise may drown it out.

I haven't tried anything other than "D" yet. I'll have to try to see if it makes a difference.

 

Possibly similar, but yours sounds a little more high-pitched than mine. Though, maybe that's just how your camera picked it up. I should pull my dash cam footage to see if it picked anything up.

 

mine does the same thing and has for the last 5 years. Something to do with the expansion valve in the hvac system IIRC. It’s random really, not specific to any speed or throttle position.

 

My 20 TRD OR MT has a whine like you all have mentioned. Honestly it is a noisy machine from the diesel sounding engine to the whine it is a odd truck. My 1990 pick up was much smoother sounding. My 18 son said “dad your truck makes some strange noises” he was comparing it to his 2015 Sierra. He also said “I don’t like driving moms car it’s too smooth”. She has a new Camry what do kids know.
If I can get 200k miles like the old truck I’m good with the noises.

 

Yup, that’s the exact same noise my 2020 4X4 DCLB sport makes. I asked about this once and was mocked here. It seems as thought it’s one of those quirks with these trucks. I’ve gotten used to it now but still don’t know what it is. Mine is 4 months old and have not used the A/C yet. To me it sounds like it’s coming from the dash area and is HVAC related?

 

https://www.tacomaworld.com/threads/3rd-gen-tacoma-a-c-noise.550627/page-19

My 2021 OR does the same thing. Really annoying sounds should not be ‘normal’.

 

Buy some mud terrain tires and you won’t hear the diff anymore

 

2021 OR 1,200 miles. Used the AC for the first time today and OMG ANNOYING. I did all sorts of speed and gear and 4WD tests and narrowed it down to the only thing that mattered was that the AC was on. Mine does it around 35-40 mph and 2,200 rpm.

 

I just spent an hour searching the forum for this, gave up and now there is a thread about the noise!

2021, started at 600miles, 1100 now and I have the same noise. Worst on hard 2-3 shifts (manual) but also audible in other gears when coming off throttle and coasting.

 

Hey guys, couple days late but made an account to comment on this post.

I had a 2016 TRD OR that I brought to the dealership when I heard this noise. They originally diagnosed the truck as having a bad rear diff, and replaced it. Sound remained, brought the truck back and they said the new diff they put in came shot and had metal filings. So I got a 3rd diff installed, still had the noise.

It wasn't until at this point they finally listened to me telling them the sound is coming from the front of the truck, and not the rear. The master tech used something to locate where the sound was coming from (not a mechanic, forgive my terminology) and determined it was somewhere in the "firewall". So he added some "sound dampening to the firewall" which seemed to help for a few months.

Ended up coming back with the noise again, to which they were stumped and started ordering parts for the AC at random. I ordered a new 2021 that month. 5000 KM into the 2021 truck and I've already had to get the entire engine replaced (lucky me) ... but the sound still remains.

Long story short, I think you're going to have to get used to the noise.