My truck is on its 4TH REAR DIFF

Whatever the problem is, its consistent, many 2016-2020 Tacomas with same problem.

 

Have there been any instances of these 3rd gen diffs coming apart. If not , maybe this noise is just that, diff noise.

 

Let the dealer make it right for you OP, remember that parts and labor from the dealership has a full year warranty on top, is not a hard job to do, maybe the guy doing it is inexperienced(?)

 

Not sure about that, is been known for 16-17 only.

 

"My truck is on its 4TH REAR DIFF"

I would of got rid of it after the 3rd one was installed.

 

Well so far i just turned 4k miles on my 2020....still no howl, very quiet. Couldn't be happier with this truck...its everything i could hope for.

 

A lot of people are saying that they are shocked Toyota is even replacing my diff, and that it is normal known issue of rear end noise, or that the dealership was just willing to appease me to get some warranty work paid out from Toyota. Allow me to regurgitate the the most recent replacement diff's repair records.

"REAR DIFF NOISE EASILY DUPLICATED- DIFF FLUID DARK GRAY WITH METALLIC SHEEN
REMOVE AND REPLACE REAR DIFF INCLUDING HOUSING- RETESTS GOOD"

So, for one they did replace the housing the last time (and yet here we are again, hearing the noise... so the housing wasn't the issue), and given the desc of the gear oil, sounds like premature wear to me. According to the master tech I spoke to today, "it looked terrible." So I do think that this is a real problem, unless this dealership is just defrauding toyota on warranty claims...

Now, onto the update:

I drove it with the same master tech who replaced the last one, he recognized that he heard a noise when the rear window was open but he claimed it was nothing to be worried about and that many Tacoma rear ends make noise... alas, I have finally been given the "vehicle is operating as designed" line. Ironically, he immediately followed up that I don't have to really worry about it for 2 years and 25k miles till the powertrain warranty runs out, just to really rub the bullshit in... When we got back I asked them pull the magnetic drain plug and look at the fluid and plug but quoted me 200 dollars for the 4 quarts of gear oil and the tech said that some metallic flakes are to be expected anyways, so I just threw my hands up and went home. Seems to me nothing would convince these guys that there is still an issue, despite my insistence that it is the same noise as the last 3 times... almost as if someone was strong arming them. My hypothesis is that they talked to Toyota corporate, and corporate said no more warranty work was going to be issued on this problem, and to make me go away.

My contention is that IF the diffs in the past had premature wear, as described in the work desc, then the current diff is going to prematurely wear based on the exact same noise. There is less than 1k in miles on the current diff, so I doubt there is too much premature wear anyways. I'd like to see it again in 5k miles, but I don't intend to.

That seems to be where I am headed. Going to sell the truck asap while used prices are high. I am not going to risk putting in a new rear end on my own dime. Just a heads up, anybody looking to buy a White 2017 TRD OR access cab, take it for a drive with the rear window open first...

 

That's simply an incorrect diagnosis. You will have metallic flakes in used diff fluid and we've beat the poor noise horse to death.

 

Hate to tell you this, but that is slightly shallow pattern

 

It's also a Drag racing only setup with Billet aluminum full spool and Pro series ring and pinion made from 9310 grade steel and special finish done to the gears

This is my Street gear setup with Billet aluminum full spool and ring and pinion have a special finish on them

 

You’d think they would have called in a master tech after 2 different jobs @ $3k each?

Maybe it’s time for a whole axle assembly? Something is not right. 3 diff failures consecutively means something is really wrong. It’s probably not “bad parts“.

 

Cool. What ratio are you running in both?

 

3.89 gear

 

Thats nice. I'm going to be installing a traction device and probably regear on a 2018 Camaro here very soon.

 

I concur, its shallow

 

Let’s be clear. Noise is not failure. I don’t believe he said any of them have failed. Ie. Broken ring or pinion hear. Failed bearings, spider gears etc. just noise.

 

Yup, and that dark gray with metallic sheen in the fluid after the 3rd has been replaced on the first fluid drain is phosphate coating.

 

Well I guess if you consider “Scored Bearing” normal. All is good.
I don’t think any bearing in the diff should be “Scored”.

Metal particles are NORMAL.
Typical you’ll see more particles soon after a fresh install. With the amount tapering off after the first 5k miles.

I personally would change the fluid on a new gear set @ 500 miles.

 

Which ones were scored. Did they disassemble the entire diff and inspect each bearing?

 

Don’t know. All I know is what the OP said “"SCORED BEARING AND METAL IN FLUID."”

I agree with you that noise doesn’t mean failure. Nor does Metal in the fluid.
After 3 Diffs someone else needs to take a look. Someone is overlooking something. Or the noise is NORMAL an the service techs and OP don’t know any better?

I’m not at liberty to say.
As I have not driven a 3rd Gen long enough to know? The one I drove had less than 20k. It’s was the neighbors and I only used it to get him back and forth to his Dr. when he need some one to take him.