Trying to figure out this noise!

So I just bought this 2006 Tacoma in the summer with just under 80k on the OD. I’m noticing more and more a Low pitch Humming or Wirring noise while driving. I believe it’s coming from the Trans because I don’t hear it when idling or revving the engine. I hear it most around 45 MPH and under, once I get to highway speeds I’m not able to hear it. Anyone out there in Tacoma world that knows what this is and how I can fix it? Also forgot to add that this sound starts as soon as I put it d and start moving.

 

What engine and trans do you have first of all, and it could be low fluid

 

4L V6 Automatic

 

Sounds like it could just be low fluid

 

Check belts

 

Sounds like the ECGS bushing fix for the front diff may be in your future.