Humming/Groaning Noise at Speed

Hey curious if anybody has ideas on what to look for...
I am getting a somewhat loud humming noise that increases with speed. It is not tied to engine RPM as I can shift to neutral and it is still there until i slow down.
I've checked everything I can think of..
Front wheel bearings replaced (bought from 05Taco4x4) roughly 30,000mi ago. Feels tight and no noise when jacked off the floor
Rear u-joints and carrier bearing replaced about 30,000mi ago (Spicer joints and OEM carrier)
All new control arms, ball joints, coilovers, leaf's, and front brakes 5,000mi ago
ECGS front diff bushing upgraded same time as new suspension.

Tried placing in 4WD, the typical test for a front diff bearing even though mine is already upgraded....no change.

Tried swerving drastically both directions, typical wheel bearing test even though a thorough garage check shows good, no change.

I'm not sure what else to look at. CV axles don't seem to have any play or make any clicking while turning.

Thought maybe it was tires and road noise, but have BFG KO2's in very good shape and the noise is even present on gravel roads. Kind of rules out tire on pavement noise.

It seems as if i can slightly feel a vibration in the floor, but that might be in my head.

I'm lost on what else to look at. Definitely sounds/feels like it is in the front of truck, not the rear. Sound level is directly related to speed. On the gas, coasting, brake pedal and gas both, nothing makes the noise change.

Any ideas?

 

Have you checked your rear diff fluid lately? I know you said it feels like it's coming from the front, but sounds and vibrations can be deceiving.
Beyond that, I would have guessed drive shaft since it sounds like it's drive train related.
By 'rear u-joints' do you mean the rear most, or all of them in the rear drive shaft?

 

Well, I changed the rear diff fluid probably 10,000 miles ago or so. Although I haven't checked the level since. No leaks though.
I did all U-joints on the rear shaft.
This is an '08 and just turned 200,000 miles. Truck is in otherwise great shape, so I have been trying to be proactive on changing some wear items out as well as a full suspension rebuild about a year ago.
Never had any mechanical issues at all with this thing since new. Literally none! So this is kind of a weird one.

 

This noise came before the upgrades, or after?

 

Just started maybe 1000 miles ago.

 

I’ve figured out a few of my trucks noises on a tow dolly believe it or not, lol.. but not every one has one and a buddy to pull them while they sit in the truck.. my vote would be wheel bearings or a pinion angle/joint problem, but I’m no pro

 

Is this Tacoma the 4 speed AT with 2.7 4 cylinder?

 

It is a 4.0 auto. 4x4 DCSB