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

I showed my dealer proof that my 2019 did not have the TSB parts that were part of the 2016 through 2018 fix. I got a shoulder shrug and was told there’s nothing they can do since the TSB does not cover 2019 and up. it seems rare that those with a sport model having the different diff have the whine.

those are diffs seem quieter. Wondering if you could swap the off-road differential with the sport differential. Now that’s just crazy talk.

 

Just to make people feel at ease. My stock 3.91 gears never howled. I had my gears replaced with 4.88’s (Rem polished and broken in with fluid change 2x for the first 1500 miles) and they never howled at all, that is until I switched to

$28 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 gear oil from 85w-140. The thicker lube seemed to keep the 4.88’s quiet.

I do think it is just a symptom of these trucks. My next gear oil change will be 75w-110 to test if that changes anything.

 

Is the noise occurring on many 2020 models?

The 2020 manual Pro and 2WD Sport auto that I purchased last year have ZERO rear end noises after 10K miles of usage. I am not sure what was changed on 2020 models to eliminate the noise. Previously owned 2016 2WD Sport and 2017 TRD Offroad 4x4 offroad had the nuisance rear end noise.

 

90k on my 17' DCLB/TRDOR and with diffs($) and transfercase oil ($$$) changed once. No howling noises... Getting ready for gears here soon (4.88's)

 

Mine has the whine from 50-67ish. Loudest at 57-58 mph. Was dead quiet at first, then within 1,000-2,000 miles it started. I used to ride around with my rear seats folded for carrying things. Now I keep the seats in normal position because it quiets the noise somewhat. It's not crazy loud, but it does seem to have increased it's noticeable speed range after 5,000 miles now.

 

I agree, except my local dealership service department is not the most helpful people to deal with. And its not just around the corner for me about an hour away. So after frustration's it makes me less and less want to even attempt to deal with them. Last time they saw the truck was for loss of power to everything on the heating control area, and it took them 3 times to get it right, and ended up throwing parts at it, come to find out the tech broke a clip connector and it was shorting every time they test drove it. which left me truckles for weeks. 2 weeks after buying the thing. which is also when i addressed this issue with them and they tried to tell me it was the way the wind went over the truck it made a whistling sound. Needless to say the truck hasn't been back since.

 

Thanks for the data. I do not even want to stare at the rear differential on my ‘20 since it does not make noise (now).

 

Its funny because my 2013 Trd sport had similar issue's and even blew the pinion and Toyota replaced it, on my dime tho. Which is why i know exactly what that sound is. And it wouldn't surprise me at all if they are recycling out old diffs to replace the problem with a band-aid.

 

Nothing was changed for the 2020 year model. You're just one of the ones that cant hear it or simply doesn't have it. The diff in my 2020 was replaced due to this.

 

Just a little follow up to my earlier post. I really have no complaints with my ZDDP Maxx ("snake oil") purchase, and am actually pretty happy with the results considering the $14 cost.

I can still hear that the rear end is making a sound every once in a while, but I believe it's quite enough that I'm ready to say: good 'nuf - at least for now. If you weren't already attune to hearing it, you might never notice it in my truck.

A few folks here (I can't recall off hand who or I'd give you credit ) have posted info indicating that the sound is a design issue and not necessarily an indicator of weak or failing parts. This was my biggest concern and I haven't seen any indication of excessive metal in the fluid to indicate that I might be at risk.

The sound is now in a different speed range too. I seem to only hear it in a small low 60 speed range (used to be in the Higher 50s too). I hear it again and maybe most noticeably in a very small lower 70 speed range - where technically I shouldn't be playing anyway.

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Below are the mods that I've made (not always specifically to address this issue). These have at one time or another been suggested as having a impact on reducing/changing the sound coming from the rear end.

• T-SB-0013-18
  I never confirmed the parts my self, but it did seem to have some impact.
  
  
• Firestone "Ride-Rite" Air Bag Helper Springs
  Could these have dampened any harmonics?
  
  
• Lucas 10122 75/140 Synthetic Gear Oil
  Maybe the heavier oil have changed the speed range where I hear the harmonic?
  
  
• ZDDP Maxx Oil Additive
  Maybe this actually worked to reduce friction/noise.
  
  
• Hellwig 3/4" Model 7744 Rear Anti-Sway Bars
  Could this have dampened any harmonics as well?
  
  
• 265/75R-16 Tires
  Maybe the +1 Tire size changed speed range where I hear the harmonic?

I couldn't say which had the most impact, and have little to no real empirical data. If I had to think back; the TSB and the ZDDP additive would probably get my vote as having the best results for me. Of course, those are the ones that I did specifically for the rear-end noise too. The others I originally wanted for other reasons anyway.

Not sure this is helpful, but thought I'd pass my experiences along anyway.

 

Had work “look” at my rear end again it’s slowly getting louder on the second rear diff. Another TAS case was made but other than check to make sure the correct “updated” rear end was used they didn’t do much as they cant do anything unless Toyota comes out with a fix but I tried my best. I can only hope the more TAS cases made the more likely it is to get attention.
A tech an I agree that it could help if we try a friction modifier like ford uses and I might try a thicker oil but I’m not super confident it will work but I’m sick of hearing it.

 

I can't imagine adding Friction Modifier would do anything because there are no clutches in there.

 

Just grasping at straws to try anything at all to quiet it down.

 

Metallica and mud terrains.

 

I tried Royal Purple 75-90 with zero affect on the differential whine (not that I was hopeful). My last easy fix try will be some snake oil. After that I will have to look into loud tires & lift. Shame since I’m a big stock fan.

 

First time posting in this thread. Got a 2020 sport with a manual trans. Mine howls/whistles once in a while when feathering the gas but its not super loud. It seems like its just loud enough for me to hear it but anyone that has ridden with me has not mentioned it and never asked anyone if they can hear it.

Again, its not super loud but it sounds like its around 600hz or so. Also, it seems louder behind my left shoulder rather than the whole cab. This is probably caused by the sound resonance in the cab though.

I currently have just under 6200 miles on the Taco so I will make note if it gets louder. At the moment, I feel like its not terrible enough for me to try and get it fixed. It sounds like a lot of you that have had it "fixed" have problems again after a few thousand miles. I don't want to deal with that and have the howl return even worse.

 

Blackbeard, That is my largest concern. I've read all the posts on this thread and it seems that the repair isn't the actual "fix". Some get lucky and some owners experience a worsened problem. With that tidbit of information, I'm hesitant for the same "repair". Right now, the whine is irritating but tolerable , if it gets worse, Ill re-think visiting the dealer. Or more than likely, a highly qualified Diff shop.
Cheers

2020 TRD OR

 

Exactly! Let's hope ours doesn't get worse!

 

Man, there are some really great deals out there right now on Tacos. Wish they would find a fix for this already..

 

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