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

Yes, it can be constant unless you are going up hill or fighting a headwinds so that the engine is always working hard.

 

People have been waiting for over a year at this point

 

And that is the frustrating part. Everyone keeps saying something is coming soon. I thought I read a post where someone said a July TSB, well it's July. I know mine is loud enough where it's an issue. I'm going in at my first scheduled service and all I can do is hope for the best. After that, it's off to a private shop for me. If they fix it I'll certainly post what it took to get it done.

 

Well mines not that loud. I'm going to try and do a 21k review video once I get back from my 7week training in Tampa Fl. Try to hear my slight noise. Probably not as bad as most peoples.

 

When I installed my OME lift I went ahead and installed the standard shim from Headstrong Offroad. I just made sure that the carrier was centered with the mount and that the shafts were inline. Since that, I have no noticeble harmonic, before I had a very noticeable howl (harmonic).. I had assumed, before the lift, that what I was hearing was the Carrier because I had the same type of harmonic in another vehicle a few years ago. Could the angle also affect pinion bearing? Yes. But to me, the frequency was to high and didnt seem to be all the way aft. It worked for me.

 

Interesting. Was it a 400hz -450hz sounding howl? https://youtu.be/rXu61z8yiMc My guess is the angle is affecting the pinion bearing because several folks have had it isolated, on a lift, with a stethoscope to the diff.

This jives with Smitty reporting a reduction in noise after his lift.

 

I'm almost certain it has to do with angles as well. Today on the drive home from work I had it howling really good. I came up to a section with some small long rolling bumps and I kept that throttle consistent and EVERY time the bed compressed in the rear, the howling went away completely.

 

The Lexus tsb added spacers which dropped the diff down to change the angle. They probably need to do that here. It might screw with their ground clearance numbers though.

 

Do you have a link to the TSB? Pics? Is this easily done?

If the spacers were not that expensive, I would be tempted to install them myself.

 

I wouldn't, you need to make sure you are moving the diff the right direction. Have to actually measure the angles to see which direction it is off. It could be too low and need to be raised.

If I wasn't over it and trading the truck in soon anyways, I would probably make my first step measuring the driveline angles and seeing if they are even within the Spicer U-joint spec to begin with. Then, based on what I heard with the sound going away when the rear suspension was put into further compression (that is my guess, I'd have to triple check it), I would load the bed up with a bunch of weight to see at what point it eliminates the sound (if it even does). It can't take too much weight/be too far off if just rolling over some bumps on the freeway affected it. Then if that had an effect on the sound I would see if the amount of deflection would put it still within the Spicer spec if that was the new nominal and adjust to match that number.

But its a brand new $30k+ truck and if im doing that shit and spending a whole bunch of extra time/money on it just to get it how it should have come from the factory, I might as well save a bunch of money and buy an older truck to mess around with....which I've decided to do. Actually two vehicles for about half the price of the Tacoma.

Good luck!

 

Thought it was the carrier bearing

 

Thats what I was thinking of. I guess it's not for the diff, so I'm not sure it's relevant. Our noise is clearly the differential.

 

Those spacers are about a $1 each. Could be an easy test. Thing is though, would that 2mm be enough to correct the angle if that is what the issue isn't?

 

One would think if this was the issue, someone at Toyota might remember this similar situation and suggest trying this cheap fix vs swapping differentials out.

 

I am sure Toyota has already explored the spacer fix versus swapping out entire rear ends, think of the money they are spending to do that.

 

You would think so. If that was the case then why did it all of a sudden appear here and get mentioned? It corrected the same issue with the Lexus and as another member mentioned, once his shims were added his issue either went away or became not as bad. Genuine question because I've had two 2016s. The first one didn't howl so I didn't track this thread. Second one howls.

 

Can someone post a parts diagram to confirm that our trucks are supposed to have those washers? Then we could check to see if the are actually there or not. I would check my truck but I don't know what's supposed to be there.

 

It can get complicated at a large company. If it is anything like the large aerospace company I work at, sometimes different programs (So for example, different cars in this case) don't 100% work together or communicate with each other on every issue. I wouldn't be surprised if a "previously solved issue" was "normal" for quite some time before people started realizing that the same issue had been resolved in another product line.

I'm also not 100% convinced yet that differentials weren't just being sent back, inspected for abnormal wear, and then put in the pipeline as a warranty replacement item when they showed "no abnormal signs of wear"

 

is the rear diff the same unit in the 4 and 6 cylinders?

 

I'be checked my truck and there are no spacers or washers.

I looked a while back for parts diagrams and the only washers are on the head of the bolts.