Drive line noise

You'll find that the defect rate between Texas to Mexico is about the same,
all the same parts,
and except for some robotic welding on the body, the processes are almost identical.
You may also notice that assembly and fitment issues are lower for the Mexico Plants.
Texas and even many other Auto companies also had issues with white paint. And they are all painted by robots.

And the Tacoma is not made in Texas any more btw.
https://www.cnbc.com/2020/01/17/toy...roduction-to-mexico-as-it-invests-13b-us.html

Any slipping in Quality standards is corporate driven, not plant driven.
And from first hand experience, Mexican plants notice and report issues before the American plants do.

Other things to check to narrow down your issue is

How are the vibrations different on the brake pedal and the shifter?

what happens when you put it in S-mode to keep it in a lower gear and reach the same speed?

what happens when you turn the wheel,

what happens when you apply brakes.

If you have someone else drive,
does it sound different if you sit in the front vs the back of the truck,
passenger vs driver side,
Can you feel the vibrations differently when placing you hand on the floor, roof, left vs right windows.

 

I’m confused. First you said your truck got shitty gas mileage but you still loved the truck.

So I asked how many miles per gallon you are getting.

Then you said 18-20 which is very normal and widely documented.

I’m not sure what your latest point is. Is their a difference between mpg and mileage?

 

Don't be confused; Yes I love the truck, despite the gas mileage. I accept this is what the truck does and that it can't be driven like a sedan with the expectation of gas mileage that a sedan would get, because it's a truck. I think you pointed out that I probably didn't research the mpg when buying, you're right- I didn't.

I posted a photo of the mpg I got while trying to drive "economically" for a few days because I said I would try that, and post the results, which were better than my previous driving. I commute in the D.C., Maryland, Virginia (DMV) area [pronounced DMV "errre-yea" around here], people speed and going with the flow of traffic means poopy mpg's in a pickup I guess.

I've heard of, and seen on one (1) YouTube video, the issue with White paint. Glad mine is Cement.

You raised a good idea on the vibration narrow down; On the test ride with the tech, I sat in the passenger seat and it was the same to me as being in the driver seat.

I haven't noticed on turns. If I remember, I'll keep it at "vibration speed" on a turn (highway) later today.

Yesterday I grabbed one of those Kendon dual motorcycle trailers from OfferUp. I towed it and used S mode to keep it in fourth gear and I kept it at 45mph. On a straight away, I sped up to 48-50mph and the vibration started as usual, I let it coast and it went away when the speed dropped below 48mph. I upshifted to 5th and got into the 48-54 mph range and the vibration appeared, just as always. I let it coast and the vibration went away again.

 

My new AC V6 4wd has done the exact same since day one. Believing it is driveshaft vibration due to slightly off pinion angle at axle I tried shimming carrier bearing on driveshaft starting with just 1 washer....that small amount gave me the vibration starting at 25mph instead of 45ish LOL

 

So between accelerating 48-54you feel the hum,
and you still feel it the same when coasting until you hit the magic 48mph. Right?

That reduces the chances of it being the rear pinion angle or any of the rear drive-line angles. Unless it gets louder through that range when you really stomp on it.

Since it happens in 4wd and 2wd that reduces the chance of it being the drivers side needle bearing.

Take note if the engine is in a certain RPM range at that speed and vroom vroom it in park and see if that gives any hints.

No feeling of pulsing at the "magic speed range" in the brake pedal when you very lightly apply the brakes? If not, reduces the chance of it being a bent rear axle.
Any pulling/more vibration on the wheel when you applied the brakes slightly? Reduces front rotors being an are to look.

Next thing to try is moving tires around, front to back.
See if hum changes, moves the feeling to your seat vs the wheel.
High probability it is a tire just slightly out of balance. If you feel the change there.

 

The tech claimed the noise is from Toyota not getting the angle of the driveshafts right and that 2020 had TSB fix for it but not 2021. That, and the posts of people shimming their AC compressors to stop other noises, I'm inclined to believe something wasnt put together right in Mexico because of too many cervesas but its still within tolerance to run fine.

Ughh. I dont want to take the tires off and move them around. I'll play with the PSI a little and see what happens... BTW, even on curves/bends, noise appears. Lastly, I've been reading the National Highway Safety Traffic Administration (NHSTA) stuff on complaints from prior years and 2021, not liking what I see. Glad I don't have those reported issues.

 

Like I mentioned, driveshaft could have been slapped in by some vatos who were hungover or something during assembly

 

I have blamed the lighter weight of the access cab not compressing the rear enough to keep it within the peaceful range on the pinion angle. It is surprising that there isn't factory installed angle shims on at least the access cabs and prerunners.