accidentally got 5w20

You are fine... 5W20 is an approved oil for the 4.0 V6.

 

Thanks for all the input. After seeing all of the posts I came to the conclusion that I was pretty sure that it would be fine. But there was just one tiny little bit of doubt in me that would stay stuck in the back of my head. So just to keep myself from being worried for another 5000 miles and to have peace of mind I went ahead and changed it out for the same Valvoline full synthetic but in the 5w30.

I did some research, and in most cases it would probably be fine. Even though it was one grade lower in thickness, the full synthetic is not supposed to break down like conventional oil would. Also, Toyota accepts the 5w20 for newer models of the v6 Tacoma. The factor that worried me the most was the fact that I live in Georgia and the 100+ degree days are in the near future. I also have a pretty decent commute to school for summer classes coming up. So the summer heat and long drives coupled together were what made me want to be safe and change it. Along with the fact that yes, Toyota does approve this for their newer v6 Tacomas, but they don't say anything about this for an '06. I think if it was in the middle of a cold winter or I lived somewhere further north, I would probably be fine. But southern heat is relentless and I guess I'd rather be sure I have what I need.