Rear diff whistle/slight howl.

Wanted to get the whistle/howl looked at on my 2023 tacoma with 600 miles on it at the dealership now. The foreman drove it and heard it said it’s normal. He said each truck is set up different from factory and can make different versions of this sound.he test drove another brand new sr5 on the lot and recorded the noise for me the brand new truck does the exact same thing. I just needed this for peace of mind .

 

My 2019 howled on the way home from the dealer from day 1. Still howling at 74k miles in the 48-52 mph range under light throttle. I only notice it when driving with the radio off.

There have been some tsb's put out for the issue with mixed results. Sounds like Toyota has just been throwing parts at the issue that seems to be caused by harmonics.

 

My 2021 didn’t start until after a few thousand miles. Mine does it when I am on the gas. When I let up on the gas the whine disappears. On the gas - whine.

I’m glad there is proof it exists. I’m still going to replace the diff fluid when it gets above freezing in the next few weeks. Hopefully with some amsoil back there is is less noticeable.

 

My 2nd gen has a hint of the noise. I have to be really listening for it.

My 3rd gen doesn't make the noise.

 

Maybe I’ll do the same . Yeah mines like a slight howl/whistle . Seems to do it most around 55-60mph

 

conventional gear lube might be quieter than synthetic. fwiw, i have amsoil severe gear in mine, and i've never heard a whine from the rear diff. i've heard some slight ringing noises but i think it's coming from the exhaust.

 

You might want to check the Oil Level in your rear diff (easy to do - just remove the Fill Plug & stick your little finger in the hole to see if you can get oil on your finger, and if not then it is low on oil).
Mine was 3/4 qt low from the factory.

 

I'm still waiting for my 2020 tacoma to howl, or whistle, but so far it's not done anything. Idk, I feel I'm not getting my money's worth.

 

Was yours howling until you topped off the fluid?

 

I’ll be honest with you man I don’t know if I can live with this noise. I’m going to try and install the old tsb sound pads and dampners that go on the rear cab mounts see if that helps. Even though 2023 isn’t part of that tsb . This is ridiculous for a new truck to sound like this. For people with good ears it’s very frustrating

 

I had my diff replaced from the dealer for this issue. The brand new one has the same howl right out of the box but way less than the original and it happens at the same speed. Changed the fluid at 500 miles with Amsoil and it’s still there. There’s a guy on here who has a pretty decent explanation of what’s going on and it’s something along the line of it’s just the way it is because of the design of the system, ie diff, axel, leaf springs etc. resonance from a bearing gets amplified. nothing is wrong and you really never hear about these diffs exploding…it is f@king annoying though if you hyper fixate on it…

 

No.
I just checked it when I checked all my fluids, at 3,000 miles; and I'm glad I did, because I probably would have had a 'Howl', and worse.

 

My '21 started howling around 500 miles. Howling was consistently in the 50-60 range. I took it to the dealer and asked about diff oil change and break in cycle. They advised me that all parts are broke in by the factory. Not sure I buy that. So I cranked up the radio and trusted my warranty. Not surprisingly the howl went away when I upgraded to 5.29s.

 

The question remains why do some trucks never make any noise? It makes me wonder

 

Still don’t think we customers should have to listen to this howling on a brand new truck

 

https://www.youtube.com/watch?v=jE9exLXr26QHarmonic vibrations tuned differently in each truck from slight differences in assembly, oil, parts, etc.
Some trucks might have dampening factors why not heard.
Different speeds create different vibrations due to frequency change. Some speeds might increase the sound.
It's all physics.
Google Tacoma Narrows Bridge lol. However there is no problem in the trucks.

 

I completely agree. I wonder if we would see a trend if we took a poll on those with the howl and those without and lined that up with which factory they were produced in. My guess (and I'm not a mechanic) is that there is a slight difference in the pinion depth on the ones that howl that is based on different process or tool settings in some factories.

 

So no fix for it?

 

Mine was built in baja