Noise similar to tire/road noise. Worst at 65+mph.

^this.
what you can try is while driving in a straight lane, drift to the out side edge of the lane (while staying inside the lane) and carefully jerk the steering wheel to the other direction. what you're essentially doing is loading different sides of the truck with weight distribution. so say for example the driver's side wheel bearing is bad, drift to the right then jerk the steering wheel to the left. that in turn loads the right side of the truck which takes weight off of the driver's side wheel bearing in turn reducing the noise. going the opposite direction will make the noise get louder.

 

lift one side of the front end, grab the tire at 12 & 6, push/pull to check the wheel bearings. you can also get the tire about an inch off the ground and stick a pry bar/breaker bar/shovel under it & pull up to check it.

Be sure to check both sides. As others have suggested it looks like this is something you haven't factored out of the equation

 

Todays results:
For the 5 seconds I was able to hold 65mph on the back roads, the Honda fartcan-like drone was gone and no vibrations through the floor. I still have the low hum that sounds like offroad tires but it was more subtle.
Only thing I changed was put the old rear motor mount back on. With the old mount, the tail of the transmission sits 1/16 inch lower than with the new mount.

There aren't any places to really hold 65mph out near my house so my way to work Monday will be the real test when I can hold highway speeds for a while.

Other things I checked that seemed ok:
1. Checked all suspension and driveline nuts/bolts are tight.
2. Front on jackstands again and tried to wiggle and pry on front wheels. No play in any direction other than making the steering wheel move side-side.
3. Spun each front wheel listening closely. No sounds other than brake pads. Held a hand on the coil while turning wheels to see if I could feel any pings or grinding being transmitted. Nothing.
4. Lifted one rear wheel at a time with trans in neutral and turned wheel by hand. No grinding or popping noises from either side.
5. Put rear axle on jack stands with trans in N. Turned wheels by hand. Then turned shaft. No odd sounds along driveshaft or at either wheel. Didn't feel any gringing or popping being transmitted into driveshaft.

So, I think it's driveline vib from that mount changing the angles just enough. We'll see tomorrow. If there is something off with the driveshaft, the stiffer rubber on the new mount might have transmit more of the vibes that I was able to feel in the floor.

 

scratch that. never mind.
I finally had enough open multiple lanes of hwy to hold 65mph and try lane changes.

I'm calling it wheel bearing for now.

Going back to the old rear motor mount did make things less harsh but the noise & vibe is still there.

A really abrupt right turn makes the vibe/noise completely go away for a second before I have to straighten back up to stay on the road. I'm talking like emergency swerve jerk the steering to the right is what it takes for the noise to stop and it's back as soon as I start to straighten out.

So, next question:
A what point does it become unsafe to drive on a bad wheel bearing?

 

When your hub falls off.

 

Your first post you said you can't exacly pinpoint the origin of the noise and you can feel it in the floor.

I still think you have a bad carrier bearring. FYI, the carrier bearring is much easier to change out then a whell bearring. Those WB's are in tight!

If you can't detect any play in the wheel and you think it is a WB, you have some time before it will need to be changed. It will just keep sounding worse and you will get to the point that you will hate to drive it. It will also embarass you if you have a passenger.

 

New wheel bearing didn't fix it.
It did get rid of the gritty noises when I spin the tire by hand.

Still sounds like aggressive tire noise once I get over 30mph.
Maybe I'll try something else this weekend.

Swerving left makes no change in sound.
Swerving right makes it go away completely.

So I still think it has to be steering or suspension related.
Wouldn't make sense to me for turning to affect driveshaft (or its bearing).
Rotated tires didn't change anything. Still can't tell where the sound is coming from exactly.

If I can find a small bottle of limited slip additive, I might add 2oz to the diff just to see even though the Valvoline guy said I shouldn't need any.

 

correction. It was a wheel bearing. I just should have changed both sides.

 

I have the same noise on my 08 tacoma 108k miles. Thank you for sharing. Time for me to order the parts.

 

A good time to purchase. My volume is a lot lower right now due to my week off at my 9/5 putting more time me to building a

 

I Have 4x4's on stock

www.jerseybuilthubs.com