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

My 2020 had the whine. I fixed it last week with an oil change and 10 oz of Archoil 9100. Mine has 10k miles. Still has whine, but very hard to hear. before the change, it was loud!

Also, the diff was 1 quart low of oil from the factory.

And my Auto trans was 3/4 of a quart low.

Glad this forum tipped me off to the shotty QC from the factory.

 

Noticed a slight whine at 45-50 mph when rounding curves, but assumed it was the wind hitting the tonneau cover. Well after 1700 miles its completely gone, even the transmission is shifting closer to normal like my tundra had.

 

I heard it in my 2017 4Runner and now my 2020 Tacoma around 50 when coasting. It's not loud but noticeable.

 

You believe the Archoil 9100 helped the noise? mine is fairly loud so a 50% decrease would be great.

 

I can't speak to the Archoil 9100, but I feel like the stuff I tried here helped a little and it was cheap enough that I couldn't see why to not try it

 

I'd like to do a little follow up on my 2020. My 2013 , which I loved, never had any type of wind noise/whine. So when I bought this one, it was upsetting to hear the "whine". I then did the research here on the rear diff noise, I decided to let the dealer service dept. know my concerns. At the dealer, and I was very prompt for the appointment time of service, I went through the explanation of my concerns regarding the fluids. All of them. I ask for them to check and verify that they were filled to proper levels. I was also there because the trans was constantly hunting for gear and it drove me crazy. Truck had around 2000 miles on ODO. The next morning I was notified the truck was done and ready. OK, picked it up and read over everything that was supposedly done. "reflashed" trans. (or something to that extent), All fuids check normal. Hmmm, I looked at the rear diff, no residue, no wiped down areas, Hmmm. I had doubts of anything being done except for the trans digital reflash whatever.
Truck now has almost 6K on ODO.
Raining here today and thanks to CV19 I have no work. So I decided to check fluids myself. It still whines.
Rear diff accepted one full quart of synthetic gear lube before filled to bottom of hole. (thats a 25% addition).
Front took almost 1/3 qt. (25% addition)
transfer case was full.
I have my doubts on the transmission being filled to recommended level.
Since I dont have the experience to check it (properly) ( ok, Ill admit I just dont have the desire to go through the B.S. to check it as described here on the forum. And , it doesn't seem to be a very precise way of doing it.)
I'm debating on just adding 1/2-2/3 qt. and calling it a day. Most here have reported about +-1/2 qt. low.
if its a little low, it should help, if its at the correct level now, 1/2 qt shouldnt hurt.
my .02.

I'm going to drive the truck at whine speeds later and (fingers crossed) , it may help with the noise.
next step will be the "zddp maxx" snake oil.

 

Ordering some snake oil today. Worth a shot since I’ve lost all expectation getting it fixed.

 

Yes it helped. I've used it for nearly 10 years with no issues.

 

Did you ever try the stuff before you went to the 75/140?

 

what trim is your truck? The rear end noise really seems to plague the DB22 diffs found on the Off Roads and Pro’s. Seems like a lot of people with SR fives and sports get the problem to go away with different oil or a differential switch. The DB22 is just f*** and Toyota keeps on using it.

 

Is this the stuff?

 

Can anyone explain how these diffs are “f***”? I’ll wait. There’s no mechanical/reliability issues with these differentials and time and mileage have proven it. They whine. Got it. Some leak. Wow, easy fix. What they don’t do is spontaneously combust or leave you stranded. Neighbor has 2 3rd gens, 1 a trd offroad and 1 an SR5. Between the 2 trucks he has almost 400k miles and he tows and hauls basically everyday. He says both his diffs do the same thing. People here seem to often confuse unrefined with unreliable. Live with it or get rid of the truck if it makes you so unhappy.

 

I have a 2012 and I have always heard that. Almost every 4wd vehicle makes a little noise as soon as you let off throttle, sounds like a higher pitched whine. Doesn't bother me... not leaking, runs like a champ...

 

2020 SR 4x4

 

You know, I do have the whine on my 2020 and it has started to get on my nerves, but reading your post honestly changed my opinion on it. I feel a little better thinking of it that way. Thanks for that

 

^^THIS^^ right here people!

 

No, I’m afraid not. I went the other way and changed to the 75/140 first. That change didn’t make an appreciable difference so I added the zddp max.

 

Mine sounded like a kazoo.

 

I mean you gotta figure too that Toyota has sold nearly a million 3rd gen Tacomas since they were released. If they weren’t mechanically sound, there’d be well documented cases of diff failures, especially here on TW.