A strange whistle at 2000 RPM or so...

OK guys... I have a 2021 TRD Off Road 4WD. It has less than 2000 miles on it and has an odd whistle at times. I plan to go to the dealer with this, but I'm afraid it's one of those things where they will keep it for a week and not be able to find the source. So, I thought I'd ask here first...

The Sound:

The whistle is slight and if you are into old cars, sounds almost like a bad vacuum leak or maybe some other kind of wind noise. It's fairly quiet, but you can hear it over the radio.

The Source:

I think it's coming from behind me... but I'm not 100% certain of that...

Reproducing it:

The sound typically happens at low load and at just under 2000 rpm... Oddly, if it's under 50-degrees outside, I can't reproduce the sound.

If you told me you wanted to hear the sound, I'd take you on the highway, get up to about 55mph, and then feather the throttle to keep the motor at around 1800 to 1900 rpm. Usually, it will do it for a few seconds and then stop.

*****

I know this is a weird issue to bring to a forum, but thought I'd ask just in case this is something common.

 

Nothing is to weird for here

 

It sounds like it may be the rear diff whine. Very common on 3rd gens. Right at 55-60 mph and feather the throttle. Mines not bad and has gotten better after 20k.

 

I would buy that... Now that you mention it, a gear noise could be misconstrued as wind noise...

 

In my 2020 that’s 3 weeks old I hear a strange low level, whistle like sound randomly. Don’t know how to replicate it. I’ll have to watch for it and see if it happens while on the gas pedal or not.

At this point it sounds maybe like a HVAC issue coming from the cab somewhere. I’m guessing the dash area.

It hasn’t gotten to the point of concern yet. If it gets worse, louder or other family members say something then maybe I’ll mention it to the dealer.

 

it’s common to be one of two things.

wind flowing over the holes in the LCA’s or the rear diff.
or
when I barely had it with stock gears, then I got 4.88’s and it went away with 85W-140 gear oil. However, after I switched to

$30 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 (after 8000 miles) it came back slightly (heavier gear oil does hep with the harmonics of this whine). So, long story short I use Amsoil 75W-110 with no noise now

 

I definitely have this on my 2019. I've also determined it occurs most frequently when i'm towing. Must be a certain RPM/load that produces this noise. Never a CEL and no issues in 10k miles. I consider it normal...

 

This is happening with my 2021 Off Road and I’m at 1800 miles. Exact scenario you mentioned. Whistles for like 1 second and usually at about 1700 rpm above 55mph. Has been doing it since I got it with 600 miles on it and hasn’t gotten worse. I can’t tell exactly where it’s coming from but it seems to be from the rear. I also had my first experience with the traction control racket today when starting from a stop on a hill. That’ll make your heart drop.

 

Turn your HVAC stuff all to Off next time. There is/was an Air conditioner refrigerant level issue. Search here for evaporator noise or such and you should find some helpful info.

 

Search here for rear diff whine.

Welcome to the club.