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

Appreciate the feedback, only going based on my limited knowledge from what's shared here. Thought the MTs had this happen more.

His biggest comment was that it doesn't happen all throughout the range, only at certain speeds... therefore, it doesn't sound like a wear whine and he's experienced this in other makes and models... makes sense...

Again, just sharing, open to feedback.

 

Hearing it at only certain speeds doesn't mean that it's not making the sound at other speeds. The human ear can only hear certain frequencies.

I had a differential replaced in my 04 4Runner. The new differential made the same sound made Tacoma differential makes. I returned it and they fixed it. In my mind, if it can be fixed that implies that it wasn't set up right.

I equate it to bad weather stripping on the doors. If it leaks just a little and won't cause damage to the interior does that mean it's normal and I should just get over it? I don't think so.

Also, if the differential was loud by design it wouldn't have waited for 500 miles to start howling and it wouldn't have gotten louder and start happening at a wider range of speeds.

I'm not afraid that it will fail catastrophically, but that doesn't mean that it's unfixable or normal.

 

Fair enough, you said they fixed the 4Runner rear differential. How did they do that?

 

I had an independent shop put their mechanic and his stethoscope on the truck. They heard it at two ranges, all while not under load.

One of those ranges I still can't hear - even though I have been told it exists.

I'm getting the same info as Berto is - from two independent sources . While the noise may not be "right" it may or may not be "damaging".

We already know that the entirety of the second gen model run had the same noise at roughly the same range. No arguing with a factory TSB....

In other words, this has existed for awhile.

Berto brings up and interesting point. The stethoscope was run while my auto was in regular mode. I may bring it back and have them run it in sport mode and see if in certain gears the noise does not exist.

 

I bought it with 120k on it and it hadn't been well cared for. I ordered a drop-in 3rd member from ECGS and swapped it out myself. When I noticed it howled the following day, I sent it back and they sent me a new one which is quiet as a mouse.

Differentials aren't easy to set up right so even pros like ECGS get one wrong occasionally. Imagine cranking them out by the thousands in some factory in Asia and it's not hard to believe why so many get botched.

 

Thanks for the feedback everyone, so far my dealer has been pretty helpful, or they seem like it... will keep going through motions and hope to get this resolved.

I do want it to get fixed, but at least I have some peace that I have time to fix it without the expectation of it grenading.

 

Not sure if this has been mentioned my anyone else yet but my whine seems to have disappeared after installing my lift. Although I do expect it to return, I wanted to add that but of info here.

 

Yep, that seems to be the effect on raising the driveline angle--which is one of the theories. Keep an eye on the noise as some members have found it to come back with time.

 

I've heard the driveline angle theory too, but I think I've ruled it out in my own mind.

It would explain how a differential would be quiet at first but develop a sound over time. It wouldn't explain why a brand new replacement differential would howl immediately though. Wouldn't it take at least a little time for the extra forces that the driveline angle puts on the pinion bearing to cause wear, slop, or degradation that would lead to a sound?

Admittedly, I'm not an expert. Replacing a differential is easy and I've done it twice but I've never set one up and I don't have an intimate knowledge of the interns and how they work as a system beyond a very basic understanding.

 

So the Toyota dealer called and they informed me that it's the rear differentials magnetic plate?? That is making the howling sound. They're trying to close out the case at this time.

What is a magnetic plate??? Sounds like bs to me. I asked them for the documentation stating that.


I have a appointment for a test ride at a drive-line shop tomorrow. Recommended by a local mechanic.

 

What?

Time to google that. Magnetic plate

 

Doesn't exsist ha. I asked them for that document in writing. Still waiting for it to show up in my email. I think its absurd they're making parts up that don't even exsist on this truck.

" all them make this sound. Normal characteristic of the vehicle. " Yeah okay...

 

Nearly 2k miles in since the rear differential was replaced and NO whine. Truck seems to be what I paid for at last. Had to have dealer fix window molding for kazoo sound, plug control arms for sound, repair adhesive on hood, fill the transmission to the proper level, torque the u bolts. I still have surge at cold start, but I can live with that. By the way my differential howl was at all speeds as soon as I let off the gas. It whined. Easy to hear and probably why I received a new rear differential. It is pretty sad with all the automated manufacturing that quality can't be better and more uniform. This might be my last Toyota. Prior to this one Prius was burning oil at 85k and seems to be consistent with what was reported with other Prius owners. Had 3 Toyota's prior to that one and they were good.

 

Maybe they were talking about the selectable locker??? The Drain Plug is magnetic but that would have absolutely nothing to do with noise.

 

Glad that worked out for you.

Was the whine louder between 50-60ish?

 

Honestly I can't remember. It seems to me that the faster I was going when i let off the gas that the whine was louder, but it might be simply because I was going at a higher rate of speed. I didn't associate the noise to any speed range. It was just annoying and concerning. It really made me think I might have to trade this truck off for a Ford full size and I really didn't want that and wanted this truck to work out. With all the problems I had with this truck at least the gave me a 125k plat warranty back when I first had all those initial issues. Regardless if this truck continues to be a problem I will likely take a serious look at the Ford Ranger and forget about Toyota for good.

 

I spoke with the Dealership manager. I told him my situation and how I was not accepting their diagnosis of the " magnetic clutch, plate" whatever silly fabricated term they're coming up with. He'd mention how my case was " well documented. the other dealership remarked how it was normal also". I said yes they told me that before. But they were willing to replace the differential! " Ok. well I'm going to escalate that with my regional manager and well talk next week or so". I said ok thats fine. I'm taking it to a independent shop that does driveline stuff all day... Also you can refer to TSB-0057-13 for the 2nd generation Tacoma having the same issue also if you want documentation.

I swear its like pulling teeth with Toyota... If I would have stayed the course with truck No.1 I would have had a new differential by now. But since they did the swap for truck No.2 I find myself meeting more resistance now.

 

That sounds more like a typical bad ring and pinion set up.

What I'm experiencing isn't really. Its more like resonance from something. Or like a tuning fork.

Which is why it surprised me when Toyota diagnosed my first diff as bad pinion bearing. Bad bearing typically sound bad all the time.

My guess its is something resonating somewhere and Toyota's fix will be some kind of dampener and more sound proofing in the cab.

 

Bad pinion bearing will start as a whine but it won't stick around long as that. It will soon go to a whirring with a bad vibration associated with it. I've been there before. It also didn't stick to a specific speed range, it eventually was at all speed ranges that I could hear a very loud whirring noise from the rear.

I didn't get the same impression with this diff issue. My actual pinion bearing issue experience went from bad to worse real, real quick.

 

Very odd, today, the first half of my ride home from work, the howl was all but gone, very faint whine, so faint most people wouldn't even notice it... came back a little, but not near as loud... the day before I go to dealer for "fix"... I will try to ride with tech tomorrow.