humming noise experienced while highway driving

[aogmike]

2018 TRD OFFROAD
i have something similar.
The difference from your noise to mine is the decibels rise and lower like a bad idle no matter what speed or what gear just as long as it is a steady speed. The rpms do not change but the noise is that constant sound with decibels going upppp and back downnnn.

My thought is not a moving part.

Sorry I couldnt help you but I was wondering about your decibel range.
Constant tone or fluctuating?

 

[4Rman]

2018 TRD OFFROAD
i have something similar.
The difference from your noise to mine is the decibels rise and lower like a bad idle no matter what speed or what gear just as long as it is a steady speed. The rpms do not change but the noise is that constant sound with decibels going upppp and back downnnn.

My thought is not a moving part.

Sorry I couldnt help you but I was wondering about your decibel range.
Constant tone or fluctuating?

Bump...

I have 19 TRDORP, having the same noise where @58-62mph i hear a cyclical noise like a sine-wave. I also feel like I have bumble bee attached to the left foot well area... and feel it a bit in the steering wheel. I have checked the needle bearing/CV axle for play and there is slight play present but can't tell if that is normal. I only have 7K miles so can't imagine that already going out. In addition, my VIN is not covered under the TSB issued for needle bearing noise as it was assembled after the TSB date range. I know if I take it to the dealer they will say can't duplicate and blame the tire hum from the AT tires - Goodyear Ultraterrain in (P) except those were on before the noise started. The tire and TRD wheels combo weighs 72.5lbs. Any insight would be appreciated.

 

[badattitude]

perhaps the pinion bearing in the rear third member. If you were ever low on gear oil it can cause the pinion bearing to degrade and make noise.

 

[Jivewalker]

What tier pressure are you running? Is there any wear on the inside of front tires? Hi LO wear will cause similar noises. Alignment and balance good?

 

[4Rman]

What tier pressure are you running? Is there any wear on the inside of front tires? Hi LO wear will cause similar noises. Alignment and balance good?

Thanks guys for your responses. To "badattitude" response; not sure if a new truck would come in with a unfilled or lower gear oil diff level to cause damage but I suppose it is possible.

As far as tire pressure, I have tried 30, 32, 34, and 38. Tires only have 2500 miles so no unusual wear that I can see. Alignment is good with no unusual wandering other than following the slop of a driving lane. I should mention that there is no change in noise/feel in relation to 2WD or 4WD - at least I can't tell. I spun the wheels and noticed that the passenger side spins more freely and longer with the same effort compared to the driver side. Also, in colder temps, the left front wheel squeals the a bit the first couple of times when applying brakes at parking lot speeds. It only has 7K miles and it is a TOYOTA 4Runner right (my third one )?

I really hope it is not the needle bearing because dealing with the dealer is a pain.

 

[Jivewalker]

maybe brakes dragging a bit on left front? Driveline noises are a ***** once you become sensitive to them. I have a cyclical howl that I've been listening to for 40k miles now in addition to tire noise from running my TAKO's at 32 instead of 44, no idea what it is but its all I think about and hear now.

If it makes you feel any better, my passenger tire rotates easier/longer than my driver side given the same spin.

With that few miles, I'd take it to the dealer for warranty.