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

In that case though we wouldn't know if the mods made a difference. If the diff was silent for 3k miles after replacement, then he added mods, and the truck remained silent for X miles after that, then technically we don't know if it was the mods that made the difference, or the replacement diff.

 

You guys.... What came first?

The chicken? Or the egg?





You're killin me, Smalls.

I don't disagree, but damn the internet is hard.

 

2020 TRD ORdcsb Baja build, I had low speed noise (howl) and it changed to a whine at higher speeds. I installed more control arm plugs leaving only a drain hole opened. Now the lower speed howl is gone. I think without the air-dam (missing on the OR) the howl isn't eliminated with toyo plugging only the 2 top holes. I've taken note that the rear diff whine is at the higher speeds only (45+) and as stated before , only when feathering the throttle, and when everything is well warmed up.
Has there been any trials of heavier weight lubes in Diff? (75-140).

 

Yes, people have tried heavier gear oil with very limited success. I do wonder if changing it out very early, maybe before the howl, would make a difference, but I have not seen anyone say it makes it go away after it starts.

 

Hi eric. Is your higher speed howl from ~45-60 mph? Does it occur with foot on the gas? Worse when going up slight inclines?

Few if any members here have reported any significant improvements after changing the differential oil, but there also aren't a lot of data points from my research. You can certainly experiment with it though as it wouldn't hurt. I might do the same.

I'm currently weighing a couple cheap, easy fixes for my truck:
1) Changing diff oil to something like Redline or Amsoil Severe Gear 75W140.
2) Adding sound dampening mat behind the rear seats.

If I can decrease the howl in my truck by at least 1/3, I'd be reasonably satisfied, and could probably live with it. Currently the noise level is higher than I am able to tolerate.

 

Ryan, The whine in my taco "appears" to be from the rear diff. Or at least the rear of the vehicle. It's only noticeable after the truck and components are at working temp. I don't hear it (again, operative word noticeable) below +-45 , and it is only when "feathering" the throttle. When Accelerating , braking or throttle chopped to coasting, the sound stops. The pitch of the sound , not volume, is relevant to speed. faster is higher frequency or tone. Slower is lower, however, all are still in the higher freq range. If the body and suspension had more of a wind or momentum shift with the throttle response, I would have more of a wind noise suspicion.
I'm not a mechanic by trade, but could it be something else? maybe the support bushing/bearing for the drive shaft? I guess I'm whipping a dead horse here, but I find it hard to believe that Toyo wouldn't contract a different drive diff or make the needed changes to eliminate this apparently not so uncommon issue.

 

BTW, it doesn't stop at 60mph. I can be at 80mph and feather the throttle to not a pure coasting, but not holding speed either, and the whine is very pronounced.

 

When my truck was new it wouldn't make the noise on acceleration, only light feathering. At around 2000 miles it started making it on light to moderate acceleration and when feathering or holding speed. I also started hearing another howl/whine in the 65-70 mph range but less noticeable due it to being at a higher frequency. How many miles on your truck?

 

All trucks whine at 80mph. Just saying.

 

I had a higher pitched whine seemingly coming from my rear (maybe diff) I have had open bed and softopper and different combos of rear mats, factory and homemade with foam. Seemed like the softopper made it more noticeable when I opened the rear window.

I did get the rear diff fluid changed at 30k, I have a local mechanic that enjoys working on yotas, mostly trucks and I follow his recommendations on changing fluids. I believe he used factory weight Valvoline oil for the rear diff. The noise is less noticeable now, but still there when I open the rear window. I DON'T like how I can't use the rear window as much as I would like...

I will try Redline oil at 60k... also might re-gear for other reasons, curious to hear if people who have re-geared hear anything?

Also... this is a truck, it has sounds, from what I am told it's quieter than previous generations, I have ran down the rabbit hole before of chasing sounds on other vehicles... it's always nerve racking

 

Btw, I just returned from driving it. I was incorrect on volume remaining the same. It is significantly more noticeable at higher speeds. Volume does increase as does the freq.
I have 3880 miles. I noticed it on day one of ownership. However, I wasn't sure if it was tire/pavement noise, wind generated noise or mechanical noise that would eventually "break-in" and dissapate.
Upon My first return to dealership to have the service dept. check out things, I relayed my concerns about this noise and wind generated howls at lower speeds, concerns about levels of fluids in trans and diffs, and the annoyance of the hood skin vibrating. Yes, my contact points to the underside frame had separated.
They only looked at trans fluid via their tech-stream (if that can be done) as far as I could tell, and topped off my wiper fluid and checked the engine oil.
I guess they have a severe lack of understanding.

Cygnus- I am not trying to be confrontational but I'm Not sure where the info comes to you from. My 2013 taco sr5 prerunner v6 did not make any driveline noises or whines from day 1 through 7.5 years and 118k miles.
My wife's MB ML350 does have a very, very minimal whine upon decel at highway speeds. But only if I'm intently listening for it. Barely can hear it. She has had her car for 5 years and I never noticed it till attempting to compare hers to my 3 month old tacoma.
My taco reminds me of the trans sounds emanating from a '47 plymouth in the black&white gangster movies made in the 50's.
evomike, yes, this truck is far (far=Holy crap!) quieter than the 2013.

 

Be sure and get your truck checked out and do what is best for your situation. My Taco was the only truck I’ve ever owned to do this. While it is true that all gear setups generate a degree of noise, they should not generate excessive noise. Mine had ground gears and excessive shavings. My pinion angle was also verified to be off. I sold my Taco and will not buy another one until this issue is resolved, and like so many others, I’ve driven Tacos for decades. I stay on this thread hoping the issue gets resolved so I can get another one. Best of luck to you.

 

I'm 62 YO. If my hearing continues to degrade at the same rate, I wont hear it any more. Working at airports and the shooting sports when young and invincible has taken their toll.

 

For months I jokingly said this is nothing a good set of mud tires won’t fix! But, sadly, my truck had a lot of other issues so I decided to bail, but stay on top of this issue in hopes it’ll get resolved because I’d like another one.

 

Anyone find a magic fix for this yet? lol

 

they sold it and bought a Honda

 

I bought a 4runner.. Next best thing.

 

Okay, okay... so I've always been a sucker for a good bottle of snake oil.

My howl was never really all that bad, but you bastards on here got my OCD all riled up and I couldn't un-hear it.

I had the TSB's performed (tech was nice enough to warn me not to expect much), bought a Hellwig Rear Anti-Sway bar (which I love by the way), changed out the Rear-Diff Gear Oil for 75W-140 Weight, and added new Subaru Tweeters to the dash - but the howl was still periodically driving me nuts and I was just about to take up @TheRealMoondog on his suggestion

So... I bought a little snake oil and put 2oz in the Rear-Diff, 1oz in the MT, and 1oz in the Transfer case - didn't mess with the Front-Diff as I'd need a 3rd bottle of snake oil.

Can't really give a definitive review of the results yet, but I have to say that this morning... I had to really listen hard with the radio off to hear the rear-end talk to me. Now, it was raining on the way in and maybe the extra road-noise made a difference, but usually at least once on a commute I get really annoyed by the howl - and today I did not

I'll post again when my drive-train completely seizes or if the howl returns, but at least this morning the placebo is doing its job - might should have tried a little sawdust first.

 

5200 miles now since driving off the lot. Off roading almost every weekend on trails and forest roads. I swear I didnt hear this howling above ~62 mph before, but today I could hear it all the way up to 67-68 mph. So from the 50 mph- 68 mph range I can hear it now. It's most noticeable at 57-58 mph.

This is the least of our worries right now in this strange time, but figured I'd mention it. I think it's gotten worse since off roading (I don't beat on it offroad). The noise level isn't louder, but I can hear it over a more broad range now unfortunately.