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

I get that very often. I have no idea why. Some days it's pretty evident. Other days, I can't hear it at all (Windows up and radio off). I take the same back roads to and from work so it's not elevation, incline, or decline. Who knows.

 

No dice, still there but more faint. Almost not noticeable unless you are listening for it. Scheduling a follow up as tech was pretty helpful.

 

Thank you to all the previous posters. Mine just started howling at 3000 miles and I took it in for appraisal and it goes in for a new rear end next Tuesday.

 

Keep us updated! Hope it's a final solution for you.

 

New rear after first visit? Was it loud? Also, MT or AT?

 

I stopped by the independent driveline shop today. Went for a test drive with the service manager, oncue at 54 miles an hour he was able to hear the whining or humming sound.

He believes it's the gear setup and would like to take it apart to see how the pattern is set up by Toyota to further diagnosis it.

He told me he has at least five or six second generation Tacomas, that he does a month with bad carrier bearings on the second gen to come in for service.


He suggested that I keep driving more of them at the dealership on test drives to determine if all them make the sound.

He seemed very interested

 

I spoke with Professor Kelly from the:
Department of Automotive Technology
Weber State University



here's a video that he did, while doing the Diff setup on a tundra.

https://www.youtube.com/watch?v=dAqAqODmcj4&t=345s


here's what he sent:

I do know that Toyota Training came out with a new class on how to setup differentials a few years ago. I suspect it was in response to customer complaints for their Tundras, Tacomas, etc.

Once the differential is removed from the truck, proper setup of a differential can take 2-5 hours depending upon the individual machining differences in each axle housing, differential case, gear, bearing, and shim. (Anyone who tells you that it does not take that long does not know what they are talking about and you should not have them work on your truck)

I just helped one of my students setup the rear axle in his 2010 Chevrolet Camaro this week. It took 5 hours for us to get everything adjusted and setup properly with the correct contact pattern in the end. (And I know what I am doing, have all the proper tools, parts, and shims)

I tell you this because most Toyota service technicians will not put that much effort into setting up an axle because the pay to perform that task under warranty is very low (~1.5 hours). Additionally, most service technicians do not know how to setup an axle properly (even after attending the class).

Proper setup of a differential also requires that the dealership parts department has the proper shims in stock for the technician to use (This is rarely the case). I had to order shims from my local Toyota dealership to shoot that video you watched. It took more than a week to get the shims.

There are almost 30 different shims that could be used in your differential, but only three of them will actually end up being used when the setup is complete.

Proper axle/differential setup is becoming a lost art.

What do I recommend that you do? Ask Toyota service department manager or Toyota customer support (Phone number in your owners manual) to send Toyota Field Technical Specialist (FTS) to investigate and repair your axle. They will have a much better chance of getting it done correctly.

The basic steps for proper setup are as follows:

1. Set the proper pinion bearing preload to specifications
2. Set the ring gear backlash to specifications
3. Set the proper side bearing preload to specifications
4. Run a contact pattern check
5. Make any pinion depth or backlash adjustments necessary to correct the contact pattern

It does not sound that difficult, but it is.

Feel free to share my contact information with any Toyota FTS if they need help/advice

Best wishes!


John D. Kelly | Professor
Department of Automotive Technology
Weber State University
1465 Edvalson St., Dept. 2404
Ogden, UT 84408-2404
Office: 801-626-7183 | Cell: 801-791-5807
jkelly1@weber.edu | www.weber.edu/automotive

 

Tnt,

Thanks for the PM and response. Very informative response from Professor Kelly there. That really outlines all the conditions and requirements to have a proper gear setup. Not only that but he shows that they had failed to do in the past correctly therefore the required training class.

 

Having done multiple diffs I can attest this can take all day. Get to step 4 and if it doesn't look good.. start back at step one.

It's a little easier with a third member, like Toyota has, so you can do it all on the bench.

 

Mr. Kelly's the man.

Assuming it's a bad set up, I'd say it's more like the 5 hour estimate. If it was set up properly from the get go, they'd have a good starting reference point; they might/could nail it the first time. As is, they wouldn't, and would need at least 1 teardown to adjust things.

 

I watched that entire video. Neat info for sure.

 

So are we under the impression this is the issue? I'll watch the video... but what's the cost to have someone do this vs doing it yourself, I'm a DYI if it will fix the issue and I can go on with my working car. Have rebuilt motorcycles and engines, so I am fairly handy with tools.

 

Don't these rear diffs come as a preassembled unit. There's not that much adjusting the mechanic can do to the gears on installation.

 

It strange to me that Toyota is willing to spend money replacing diffs rather than trying figure the cause. But them willing to fill their lot to wait on the recall parts shows they're not willing to take chances on a lawsuit.
Could this howling just be the result of shitty work but not enough to create issues or premature wear down the line (where safety isn't impacted as well) and Toyota is too daft to tell us "sorry, we fucked up but you're gonna have to live with the noise..don't worry, it won't break on you"?

 

Like I said the driveline shop already knows from prior 2nd Gen's the drivelines, the carrier bearings in particular go bad. They do quite a few of them a month. TSB-0057-13 acknowledges the rear differential noise, as suggests checking fluid levels and replacing it.

They seemed more shock that the newer trucks the 3rd gen are still having this issue.

https://www.carmd.com/Tsb/Download/98089/T-SB-0057-13

 

I watched that whole thing. No wonder Toyota is flaking on fixing it. None of their techs are qualified to do that. They might have one or two but that's all they'd be doing for years if they recalled/tsb'd the truck.

 

Toyota's logic.

Let's just outsource to Mexico. We have a cheap " skilled labor force". We'll save a few bucks, and offer American consumers " award winning quality control". American consumers can't tell the difference anyways..

 

They are assembled elsewhere and then bolted on. I think Toyota doesn't want techs opening them up to screw with them because it's complicated and time consuming.

So they just replace them and hope the second one is better. Their bean counters get involved and probably figure changing it out once is worth it to reduce the chance that it's dangerously broken and increase the chance that the diff supplier got the second one right.

Who knows? Maybe it's more complicated and we are all wrong , but Toyota hasn't proven overly competent in basic mechanical 101 stuff lately. I wish I had a quality gear/driveline shop near me.

 

The diffs are sourced from elsewhere and my pos was built in San Antonio.

 

Dude. This shop near me these guys are great. No bs attitude. I said Toyota Tacoma and their eyes rolled. They already know. They had a few 2nd gen's in their parking lot ha. No joke.

They checked out my truck and remarked how they changed the differential design to give more support ?? Not sure. But when I said I was having issues at 1,300 miles. They were shocked. They figured Toyota would have gotten their shit together. Then he took me back and showed me a 2nd gen differential on a table as reference. He thinks their almost the same design, just the 3rd gen is beefed up.

He wanted to take it apart to see how it was setup. But both of them were curious..