Droning Sound At Highway Speeds

Hello All!
I picked up my first Tacoma, a 2010 regular cab 4x4, in late October. It's a 4cyl with manual trans. Over the past few weeks I have been noticing a gradually increasing droning sound at speeds roughly between 60 to 68 MPH. The sound can be mild at times or fairly deep with a very slight vibration. It is speed related and only occurs when I touch the gas and while in gear. There has to be a load. If I rev the engine in neutral at these speeds, no droning. Of course the dealership couldn't hear anything. Any ideas???
Thanks in advance!

 

flip your driveshaft around

 

Thank you 650H1! Could you explain how/why the driveshaft would cause this issue? Is it possibly a balance problem with the shaft? Why would flipping it help? Thanks for your time!

 

drive shafts have weights on them and go on a certain way. if reversed the weight will be off creating a vibration and hum/drone noise.
does the truck have a lift?
i am trying to think why the drive shaft would have been taken off.

 

Thanks for the input blake5995! The truck doesn't have a lift (yet!). Would the weight be on a particular end of the shaft or would it just depend on its balance needs? Also, being pre-owned, there's no telling what may have been done to it previously.

 

I was under my truck tonight having a look. The drive shaft has what looks like a CV boot towards the front. Does it matter which end this boot is on? I was considering flipping the shaft around this weekend.

 

can you throw a pic up on here of the driveshaft or just text me one and i can look at it.
if i am correct the boot looking end should be on the differential side.

 

OK, I'll get a pic of it in the morning. Thanks for your time.

 

yea no prob always trying to help others out

 

From the factory, the boot end should be at the transfer case. I had the same issue with my reg can, flipped d shaft around and all was good...

 

Thanks guys. I was going to take pics but stumbled across the same thing 650H1 is saying. I've decided to give the dealership another shot since I still have a little warranty time left. I'll insist on going out on the road with the tech to point it out. If all else fails, I'll flip it.

Thanks Again!

 

Have the tech flip it... Toyota tech at the dealership flipped mine...