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

I thought howling usually happens when gears are too tight (too little backlash) though.

I really want to know why the noise appears AFTER miles are put on the truck. This really contradicts the NVH argument as you would think harmonics would be present right out of the gate. It doesn't make sense that these trucks are quiet when new, then start howling up a storm a few hundred miles later.

The only thing I can think of is that these gears come with a phosphorus coating (common in the industry) that wears off in a few hundred miles. It might also explain why it's common to see "excess shavings" on the first oil change.

https://mgaguru.com/mgtech/rearaxle/ra202b.htm

 

As y’all know had my diff replaced at 3,800 miles and the whine came back before I made it home approx 35 miles. Have an appointment Monday the 13th to see what the next step will be. Thought I could live with it but decided to push the issue as far as I can and see what happens. I’ve owned Toyota’s since 1985 and shouldn’t have to settle for this crap.
So far dealer has been awesome, truck has 5,800 miles as of today

 

2,000 miles on mine and it howls. Not loud enough for me to get it replaced, but I've stopped keeping my rear seats folded down. The howl is worse that way.

 

Wow. The fix wasn't much of a fix. Curious to see what Toyota has to say and what they do.

 

This thread is depressing. I wonder what percentage of Tacomas have this issue.

 

I'd bet some Tacoma configurations are affected and some aren't.

My guess is all Tacomas within the affected configurations have it.

For anyone who claims not to have the howl, I'd love to see some video.

 

What are "the affected configurations"?

I don't even have 5K yet, but still my AC Sport makes no howl......maybe I'm deaf or don't know what a howl is. Dunno what you would see in a video, but I don't have any good high quality sound recording equipment.

Can someone post a good recording of the howl?

Which one?

 

Yeah, it ain't the best feeling. Haha. I supposed eventually Toyota will really have to DO something about it if we all keep on nagging.

 

Mine is definitely not like that second video from inside the truck. Mine also doesn't make any howl over about 59 mph.

Don't know about that first video because my head isn't next to the diff when its howling.

 

I listen for ANY foreign noises naturally. I've always been like that. The second video sounds like springs to me(?) and doesn't sound like a howl. The first video sounds like a generally noisy differential.

 

Seems to be pervasive on DC ORs, that's for sure.

If Toyota is right and it's harmonics, even small differences in truck configurations could be enough to change the natural frequencies of the springs, frame rails, and cab.

This guy's clip reflects what mine sounds like

 

I'm super curious if leafs, tires, etc might cancel out the noise. I'm not there yet so I'll have to just keep following along here.

 

59 is when mine stops too. I can barely start to hear it come on around 49 mph, then it fades out a little from 51-53, then peaks from 54-58 mph, 57 and 58 being the worst.

 

EXACTLY the same in mine.

 

That ain't the diff howl. That sounds like the weatherstripping kazoo noise that was apparently an issue on earlier 3rd gens.

 

Agreed. I’ve had both the weather strip kazoo and the Diff howl. And this is the kazoo, no doubt about it.

 

So those with MT cruising along in 6th at say the loudest perceptible howl - let's say 57Mph. Or 56 or 58. Just hold MPH steady. Now shift to 5th. Keep speed the same. How does the howl sound?

 

Pretty sure its exactly the same. Will confirm later.

 

@Pablo8 Same. Makes no difference being in 5th or 6th. Confirmed twice on the drive home.

 

54 MPH is the peak level in my truck, 5th or 6th gear don't matter.