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

Has anyone coated the axle tube with rhino lining or something to see if it calms down the noise? My dad thinks it’s the thin ass driveshaft.

 

You're sort of right. On my truck I have some wildpeak AT3W's and when I swap back to my original GY's, rear diff whine is slightly present. I had the TSB done and it fixed like 90% of the noise. With the falkens, I hear 0 noise and the only time I think about rear diff whine is when I see this thread.

I also have HD dakars, but I don't think the leafs really matter much as I had no whine for 15k miles, then when it developed(60-45 decel only, loudly), ran the TSB leafs for another 15k or so miles before swapping to Dakars for the last 22K miles or so.. No difference between leafs IMO. I've had my wildpeaks since 8k miles. The noise is certainly better since I had the TSB done, but a certain level of drivetrain noise is just there. If I ran the stock tires, I'd probably be obsessed about the last 10% I could hear.

AT tires mask it. I never considered the wildpeaks to be loud tires, but as they have worn they are certainly louder than the stock OR tires.

Not a true fix by any stretch, but what's the actual problem?

 

yeah but that deep whine on the coast and feathering can be heard regardless of tires. Hell I have 5.29 gears and it’s exactly the same hahaha

 

Yeah I didn't mean to imply that my whine was the worst, others have it bad. Pre TSB i'd need boggers to drown out the noise, and maybe a 12v.

Post TSB though? Nothing really to report, but some driveline noise can still be heard. Just like every RWD vehicle I have driven, much less than my '08 Chevy though.

Ultimately I don't think leafs have much impact. Tires moreso.

 

I for some reason think the TSB won’t apply to my 2020? Shouldn’t mine already have the TSB done at the factory?

 

Yes and yes.

 

clearly the TSB does nothing then

 

At first I estimated the TSB helped mine by maybe 50% but then it just kept getting louder and eventually exceeded what it was before the TSB. Then I had my diff replaced. It was completely silent at first, only to come back after about 1100 miles. The whine was then even louder than the first diff and it was very noticeable at several different speed ranges. Mine was so loud until it could be heard over my radio with it turned up to 35, and I had the Kicker speaker upgrades. There was no unhearing it and nothing about it was normal no matter what anyone says. Like many on here, I’ve owned a lot of new cars and trucks (31) and have never had this issue on anything else other than my last Taco. Do gears make noise? Yes, but what I had was excessive. Even Toyota said my gears were ground and the pinion angle was off. Either way, no matter what the issue truly is we’ve yet to hear of these things grenading on us, but it would be nice if they’d simply do whatever it takes to fix this issue.

Best of luck!

 

I just regeared to 5.29s and lifted the truck with icon leafs and it’s exactly the same noise. So weird. No fix Toyota kinda sucks. I would rather have a Ford or anything at this point lol.

 

Only the 3rd gens have the larger differentials with the whine. I don’t think any model of the 2nd gens have the DB22 diff.

 

2nd Gens also had diff whine complaints but I don't remember hearing it when I had one, could be that the 3rd Gen is so quiet compared to the 2nd that you can actually hear it whereas the 2nd Gen has so much road noise that it probably drowns it out.

 

I would not. The rear axle/diff generates a bit of heat. I would think any coating would help hold the heat in.

 

It's been reported that not only do some 2nd gens have the whine/howl, virtually all Hino manufactured rear axles do this to some degree or another.

 

There are vents in the rear of the cab for cabin pressure. Can’t seal those off . That’s why it’s louder with the rear seat folded down .

 

I never noticed it on my second gen either. This has definitely been a tough one to get a handle on. Maybe they’ll get it figured out. It’s definitely irritating for those (like myself) that are bothered by it. On the bright side the diffs seem to be holding up.

 

Hardly. It reduced my noise by 90%.

 

It's not a 3rd gen problem. It's a Toyota problem.

https://static.nhtsa.gov/odi/tsbs/2019/MC-10164329-9999.pdf

http://media.fixed-ops.com/Toy_ServiceBulletins/sb0057t13.pdf

 

I recently sprayed a coating of cosomoline rp-342 throughout the undercarriage of my sr5 getting a light coating on the rear axle tubes and carrier. So far no howl but never had it to begin with.

 

Cosmoline fluid film MavCoat etc Im sure is fine. It's the rubberized coatings that I think would be a bad idea.

 

Well, whatever the noise is I think Toyota needs to get together with Hino and go thru every spec on the rear ends and see if they cannot track it down. Hino is the problem. Rest of the running gear is all normal stuff on a ton of vehicles. Something with that third member is causing the issue. Something in the structure of the rear end is transmitting and amplifying gear noise. It is strange that new from the dealer they are pretty quiet, then after 1-2 thousand miles they become worse, perhaps pinion is not running correctly in line to the ring gear? Something there is out of spec. Don't claim to be an expert, but I know new vehicles should not have this noise. Until after several hundred thousand miles due to ring/pinion extreme wear!

If they cannot come up with a fix Toyota needs to find a new supplier for this assembly. Hopefully a USA mfgr, Dana??