roar and vibration at 40mph

my 21 TRD OR developed a "roar" and mild vibration at 40 mph up to about 60, wheels and tires balanced and rotated, needle bearing replace with ECS bushing, any ideas?

 

I'm assuming you're feeling it in the front or through the steering wheel?

Have you checked (can you check) you wheel bearing units? Jack one side up then the other, and see if there is any amount of perceptible wiggle when pushing/pulling at the 12 and 6 o'clock on the tire.

Have you changed your diff fluids?

Do you hear anything with the windows down at lower speeds? 25mph and below?

 

Sounds like your flux capacitor is spooling up. You need to get your speed up to 88mph when it does this.

 

diff fluids changed aprox 10k ago, I checked the front bearings and hubs and there is no play noted, sound is only at and above 40