Popping Noise

Hello all,

I am completely new to this forum, never even used a forum at all to begin with so I apologize in advance if I'm breaking any procedures or etiquettes that I'm unaware of. I have a 2013 Tundra with 95K miles on it. I was coming home today and floored it with the tow haul mode on for a little fun down an empty street leading to my house. When I did, I felt a clunk that sounded like a loud knock underneath the truck in near the back seats and bed area. Have no idea what is was, haven't tried to replicate it by flooring it again in case it's something serious. It'll be getting a run through tomorrow, all the fluids changed, tires rotated etc. Wanted to know y'all's thoughts on what it could possibly be?

Thank you!

 

See if your spare tire is firmly snugged up.