Hum on deceleration

That is totally unacceptable, they are supposed to stand behind their product, and should have already had engineering on the case.

 

From what I was told, my case was actually sent to Toyota engineering. They took video and analyzed the sound heard in the cabin through the video. They deemed it an acceptable level. I posted the video I took, of the brand new differential howling (what Toyota has deemed an acceptable level) in the thread smitty referenced. I will let anyone make their own judgement as to whether or not that is acceptable. I will say though out of all vehicles, from cars to trucks, that I have ever driven, I have not heard a normal diff make this noise.

A noisy differential has always ended up a problem down the road...but Toyota promises it is ok. Ok or not, it's driving me nuts.

Others have said that field engineers have alluded to a fix being in the works, but we will see....

 

I'll certainly do that. Thanks for the great info.

 

How can people who fix hundreads or thousands of diffs say one thing and then a bunch on engineers completely disagree with them?
Seems so illogical and unfounded.

 

Because they do not spend the money to fix it correctly.

 

Looks good to me

 

Sorry I have been gone the entire weekend. I have been doing extra building on bearings trying to get ahead of the curve so I haven't been around lately.

As mentioned by others, the sound is not very noticeable on the recording, but I can pick it up. If this occurs during a light acceleration then I would say your noise is on the drive side, and not the coast side. This was VERY common on GM trucks and I replaced many gear sets because of this when it was excessive. However GM was very particular about how LOUD the noise was before they would deem it excessive and warrant a replacement of the gear set. It is honestly hard to be able to tell you from a recording standpoint on if it is excessive or not. I would say to try this:
Go to the parts store and buy 4 bottles of Mobile 1 synthetic differential fluid.
Get 1 bottle of Lucas gear oil additive.
Drain your rear differential and then reinstall the drain plug.
Add the bottle of Lucas FIRST.
Add the Mobile 1 until your differential is full.
Install the fill plug.
Go out to where you have an open area of road with the least amount of cars, and a speed limit of at least 45 MPH.
Hard accelerate until you hit 50 MPH, trying to keep no higher than 3rd gear.
Coast down to 25 while still in 3rd.
Shift to 2nd and hard accelerate to 50 again in 3rd, coast to 25. Do this again a 3rd time but this time come to a stop, downshifting as needed and allowing the engine to slow you down.
Now do a normal acceleration to 50 shifting to 4th, coast to 35. Repeat a total of 3 times.
Finally start driving normally and see if this noise is still present.

 

Aren't you the guy that recommendeda crush sleeve? What's that do / how does it work?

I'm losing my patience with Toyota

 

Toyota's come just like GM, with a crush sleeve from the factory. I prefer them myself just because they are simple to install.
Here is a really short video to show a crush sleeve install.

https://www.youtube.com/watch?v=x-tDIx3J2Po

 

Thanks @BamaToy1997 for the great info.
Yesterday I ordered some Redline fluid for my rear diff. Could I do the same expirement with that instead of the mobil 1?

Also, do you have a part number, a link or a picture of this gear oil additive? Google and lucs website is not helping me.

 

Redline will be fine. It's still a synthetic I believe.

As for Lucas oil, this is a link to the additive on their website.

http://lucasoil.com/products/gear-oil/anti-squawk-anti-shudder-additive

 

Would that void warranty and or would they be able to tell it was added?

 

I highly doubt it. The product is compatible with oils.
For everyones info I am going to do this.
I'll document it and whatnot and report back.

 

Redline is synthetic.
Thanks @BamaToy1997!

 

I was at the dealership today for the same sound in my diff. Basically a howl at 55mp when lifting off the fuel.
They did verify the sound and told me that even though it's annoying, it will not heart the truck. They are also ordering a transmission insulator to fix the problem.
Funny, no mention of a "transmission insulator" on TW befor, might this be a solution?

 

I read that yesterday as a part of a TSB for manual transmissions. I don't think they are related.

 

I'm convinced that they are not related. They explained to me that it was a vibration transfer through the frame from the transmission. Do you have the tsb# they are thinking of?
I'm know my diff is making the noise. But at at least it's documented.

 

My Redline Rear Diff Fluid should be here next week and the Lucas Oil Anti-Squawk / Anti-Shudder Additive will be in tomorrow.

 

Mine has the slight howl, but so far hasn't got worse. I'm waiting for it to increase so the dealership can't deny the sound. This is such a stupid problem that shouldn't even occur, or at least be fixed by now.

 

A howl when lifting OFF the accelerator is indicative of a wear pattern issue on the coast side of the ring gear, and is usually louder than a drive side howl. On low mileage trucks this usually indicates that the gears were not correctly installed, or proper break-in procedures were not used. On a higher mileage this indicates that the gears were wearing abnormally and are showing signs of it now.