Humming noise help- have searched

[buckeye4runner08]

Hey guys, was hoping I could get some help from the community in attempting to identify a new noise that has cropped up on me. 2008 SR5 V6 for reference.

Just recently started noticing what I can only describe as a "humming" noise (it almost sounds like mud tires, but I'm just running street tires) that starts when I am between 30 and 40 mph and once the noise starts it will maintain or get louder and more intense until the vehicle is stopped or I go faster than 45 mph or so. It sounds like it is coming from the front of the vehicle, but I am slightly unsure. The noise is present when accelerating, coasting, and is not affected by turning, potholes, or moving from 2wd to 4wd. It doesn't happen 100% of the time, generally only on smooth road with little other road noise. Both front wheel bearings were (supposedly) replaced about 500 miles ago.

So far in my research I've come up with the following possibilities:
-Rear diff is biting the dust (god I hope not)
-Wheel bearings (they were just replaced?)
-Tire noise
-Possible frozen caliper?

I've tried rolling down the windows when the noise pops up to see if I can hear it better, and it is less noticeable. If I just have the rear window down it seems like it is louder, but not 100% on that.

When I was replacing the driver's CV this past weekend I did notice that the wheel does not spin very freely on that side. There is no grinding or metal on metal noise, it just becomes hard to turn by hand at one part of the revolution, so I'm thinking I might have a brake problem but the braking is great and there is no wobble or shake under heavy braking.

I know I'm rambling but I'm trying to get it all out. What do you guys think? I'll try and get a video of the noise, but I don't think it will show up well as I tried last week and it was not noticeable in the video.

Thanks all.

 

[techno]

One thing to check is the tread wear on the front tires. Cupping will cause extra noise like you describe.

 

[gm350reratliff]

One thing to check is the tread wear on the front tires. Cupping will cause extra noise like you describe.

I would check this and also check the rear wheel bearings. When they went south on my 4th gen, they made a similar noise to what you're describing. Jack the rear up, remove the wheels and rotate by hand to see if you feel anything.

 

[buckeye4runner08]

I did check the front tires and the one that is on the passenger side does seem like it's cupped on the inboard tread. This was rotated the last time I was in the shop, and I'm not sure which corner it came off of. I'll rotate it to the back this weekend and see of the noise changes. Bad tires would be the best for me right now for sure.

Sent from my SM-N920V using Tapatalk

 

[wcjeep]

Another troubleshooting tip is buy cheap FRS radios. Tape/zip tie one to always broadcast. Move it from one place to place outside the vehicle. Should help narrow the search area. Cheaper than throwing parts at the problem. Also recommend a Flir or infrared thermometer. Look for increased heat. Tires on the sun side of the vehicle are usually warmer than the shade side.

 

[Geerlijd]

I had a similar noise between 55-70 mph accompanied by vibration in the steering wheel. I swapped tires (I own two 4th gen T4R's), no improvement.

Then I replaced the needle bearing on the front diff (look at ECGS video for needle bearing play in 8in clamshell). This improved it,but didn't eliminate it.

Finally I replaced the front wheel bearings and it completely eliminated the noise. I didn't suspect them at first as the tires spun smoothly and wouldn't wobble on a lift. When I pulled the bearings, the passenger side had a noticeable grinding feel when I turned it.

 

[DMX512]

I have a similar issue as well.
Just purchased a 2007 T4R w/110k mi., did not notice it during the test drive.
Mine has a hum and vibration when the steering wheel is turned slightly to the right, like when driving in the inside (fast) lane and I need to correct a bit for the crown in the road.