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

Toe?

 

Toe.

 

Post before that said heel to tow.

I think it's heel to toe.

 

Thought this was interesting. SILVER SHAVINGS?!?!?! That's just great to hear about your new truck. Oh yeah. And the OPERATION IS NORMAL.

 

well little tiny filings is normal for a differential usually.
if its big pieces i'd be more concerned.

 

When the hell was this done? Recently? Are they really still replacing random diffs even though it clearly doesn't fix the problem? Two people, same problem. One gets new diff, the other is told it's normal deal with it. Toyota WTF?

 

All depends on the dealer.

 

Good info, appreciate you sharing. About to be in the same boat I think.

 

I did a very mild lift, based on service manager basically telling me it was OK to stay below 2". 6112s up front, 5160s in rear, progressive 3 leaf AAL from wheelers in rear for 1.5" all around. I cannot hear the diff howl since the lift, this may lend credence to the theory of driveline angle or it could just be a coincidence. I don't think 1.5" further from the diff/axle would make a difference on whether or not the howl would be audible so it has to be something that changed the characteristics of the rear end.

You can see details of my lift discussed in this thread pages 2 to 3 here: https://www.tacomaworld.com/threads...talling-1-5-lift-bilstein-5100s.483874/page-2

Note that I was very skeptical in taking the risk to do this. I did not do it thinking it would solve anything. I did it simply because I have to keep this truck for awhile and I wanted to improve performance offroad for hunting season where I drive 100s of miles of forest and ranch roads that are not maintained. It was a huge improvement in handling and ride quality.

 

Might be something worth investigating since your case is followed closely by toyota corp. Thanks for the update! 1.5" is worth a degree or so to reduce the binding the joints may encounter. All win situation!

 

Mind.Blown.

 

I have the updated leaf springs for the driveline vibration tsb and have not had a howl....i wonder if driveline angles cause a harmonic load and unload of the pinion gear and the leaf springs fix it...

 

Looks great @smitty99

 

Sounds like a good way to get the wife to agree to a lift!

 

So here's an idea. Someone with the definitive diff howl throw in a pair of 1.5 inch spacer blocks on the rear axle temporarily and see if it goes away. If I can find some spare time I will try it. Any reason this would not duplicate the conditions of smitty's lift? @smitty99

 

I was thinking the same thing. I have a shell and was planning to add a leaf. Was going to wait until I did the lift/ tires but I may go ahead and do it early. Was planning to burn through the factory tires first.

 

Can also take it to a driveline shop and ask them to measure the current driveline angles. I have the rumbling vibration coming to a stop which I have sworn from day 1 is due to driveline angles. There is a TSB out for it now which includes measuring the angles but I believe OR's aren't included for some reason. I'm going to try to get my dealer to do the TSB. I might even offer to pay for checking the driveline angles if they can't do the TSB and the angles come back correct.

 

So I still noticed just a slight howl today on the freeway when I feather the throttle just right. It is less noticeable but not completely gone.

 

Blocks act like as a lever when it comes to axle wrap; operating angles won't be the same as a 3-leaf aal.
Measuring static driveline angles is fine...what's it doing under load, though?