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

Right on. I was thinking that maybe bigger tires would:
1. require more throttle so you don't get into the sweet howl spot.
2. bigger tire means the gear set is moving slightly slower and maybe would change the howl frequency (or speed maybe); something along that line.

But in your experience tires alone didn't change anything but lift did. Maybe a combo of the two?

Did tires change any aspect of your howl?

 

Correct. Now were tracking. I noticed my last TWO trucks started off at 0 mileage, virtually no howl/whine. Then right around 500 or so ( most critical milage for break in) it starts to produce that sound at 50-55 mph. Both trucks I had 4x4 TRD Off roads developed the noise in almost the same circumstances. My truck has roughly 3,000 miles now, after my trip out of state, I can hear it beyond the 50-55 MPH, its also now in 50-65 MPH and increasing in sound. Usually happens on crusing/coasting, becomes louder when feathering the throttle. I'm struggling to maintain normal highway speeds at 60 MPH unless I use 3,000+ RPMS. I was getting passed by pick up trucks towing trailers, etc. Very frustrating.

i'm 99% confident my pinnion bearing is shot. I can feel drag, not as smooth as before. Also a drive shaft clunk sometimes on deceleration.

Toyota says this is " normal".

 

I've actually had a shot pinion bearing before. I can promise you if yours was shot you would know for sure. It is a lot more than a simple little whine when feathering the throttle. Think more along the lines of extremely loud whirring noise (well beyond a howl) from lower speeds to higher speeds and a vibration so bad at points it makes your mirrors blurry.

The driveline clunk is normal and due to slop in the drivetrain.

The no power below 3k rpm is the engine working as designed (and yeah I agree it was a bad choice)

I'm not discounting your problem, I know the howl is very real, it was the number 1 reason I sold my truck. But I don't think you have to worry about an immediate pinion bearing failure. It gets way worse, fast, if your pinion bearing is shot.

 

Could also be the gear setup also. Specially contact pattern or back lash. That's what the independent shop told me.

 

I can't buy into the harmonic theory. In my opinion, a harmonic issue would be static. I don't see how an inherent harmonic resonance would not be present with 0 miles, pop its head at 500 miles, and continue to get louder and occur at a wider range of speeds.

My only explanation for the ever evolving noise that I'm experiencing is something is wearing fast and incorrectly. It is possible that there is a harmonic element that magnifies the underlying abnormal noise though.

 

I just have to wonder if the Kobe steel scandal is the root cause, if so, that would explain Toyota’s stonewalling on this issue. That would be a huge, long term mess to clean up if so.

 

Doubt it, that whole issue is about them falsifying raw material property data. So everything is designed/analyzed to a certain spec, where we get what we call allowables, and I believe they essentially said the raw material met those specs when they may have actually not. It's more of a concern if it was used in a structural component.

The raw material still gets machined, surface finished, etc from there. At least some parts (usually) are also inspected to make sure everything looks good. Plus there is testing of the component and overall vehicle at multiple steps.

I still believe there is a design oversight or flaw. However minor or non-safety related it may be.

 

What did you use for diff fluid?

 

Lucas synthetic 75w90. I wouldn’t expect the fluid to change the noise like a new leaf pack.

 

What? Is this post somehow helpful? Shouldn’t Toyota be reading this book?

At this point we are all just speculating. You included.

I have also set up multiple third members (Toyota) as well as a couple Dana axle ring and pinions.

I’m disappointed Toyota f’d this up and I’m happy for the chatter here.

My plan is to let Toyota fix (or mask) the problem, which has been promised to me personally, first. If it’s not up to snuff then I will try and fix the issue or sell the truck.

Thanks though.

 

I offered a source of knowledge for those who don’t understand differentials and how to set them up and what causes some of their issues. I see that as helpful for those who want to learn more on the topic. 3500 reply’s to a thread and I bet the average Joe still has no idea what is hidden inside their diff or what issues to look for if they saw one apart. My post may change that if someone chooses to learn more on the topic and orders the book.

I don’t know why your panties are in a bunch and why you are on the attack. Information was offered and you somehow got offended. I will go back to enjoying my howl free truck and not worrying about the nonexistent noise. Have a nice day.

 

Reread your post again, wasn’t as condescending as I originally read it to be.

Anyway I’m sure the book you suggest is a good one but what’s the point? Even if I do all the research to figure out the problem, Toyota doesn’t care.

The only fix at this point seems to be new non Toyota ring and pinion and lifts (for some reason).

The noise is annoying and not like any rear end noise I've experienced.

This thread has been good for us, who have the issue, to vent. So that’s what we do until Toyota comes up with something or we’re out of warrenty and fix it ourself.

 

I don't know about reading a book as a means of repairing a noisy differential. Mine was replaced 3000 miles ago by a Master Tech at a Toyota dealership using Toyota parts. It is no longer noisy. Explain that one. I have a stock truck. No lift, no special leaf pack, completely stock SR5 double cap. My guess at this point it may have to do the competency of the people that are involved in doing the work. Rather it be the manufacturing process or the dealership or the Master Tech that actually performs the repair. I shouldn't have to read a book when I purchase a 30k truck to understand potential defects that should never have been to begin with.

 

Hey that’s good to hear that a replacement worked for you.

My second diff is louder than my first

I really like my truck too but the howl is driving me nuts.

 

Honestly it was self deprecating, but duly noted.

 

Does anyone have any updates or any news to share?

 

After being denied mine through corporate and warranty, I'll just drive it till it explodes or locks up on me. Which is what Toyota wants. They got their money and contracts.

On another note I'm having spark knock on 87 octane.

 

I love mine but I’m thinking about trading it off for maybe a 4Runner and wonder if anyone has any thoughts on that. I have always owned a truck but really don’t haul anything that would warrant having one. I deer hunt but could probably get a hitch mounted carrier to hold a deer. I’m on the fence but I’m also tired of that howling. Noises drive me crazy and once I know it’s there it’s all over for me. I’m also wondering it part of the delay for the 18s is because this issue is being addressed.

 

I went to test drive the new 2018 4 runner. Very nice vehicle, it was the TRD Offroad. It was close to 42 MSRP being black and a rare bird at the dealership. Drove great, no Atkison cycle bs like our Tacomas. I also test drove a Tundra 5.7 Offroad. Wow, that amount of low end torque and acceleration was great. The suspension can take a beating at 60 MPH over a speed bump. The salesmen told me to hit it on purpose. Did freaking nothing... I braced for impact, but he knew it would be soft as a cloud. Crazy ha.

I couldn't come to terms on a trade in value. They offered me around 32-33k " oh you have negative equity". I'm only at 4,800 miles. So goto multiple dealerships but dont tell them what others offered unless they low ball you. Mine is somewhat rare being a long bed TRD Offroad and 4x4 in Magnetic Gray.

Go into the dealerships, if they know anything they'll admit to you that the 3.5 V-6 was a dumb move by Toyota.