Guess the part

Nope that's a motor mount bolt. 100% positive. Did you crawl under your truck and look at the motor mount?

Edit : I see you found it

 

Yep you were right!

 

Here I am over a year later and I'm still dealing with these stupid engine mount bolts. Every few months the bolts on the driver's side engine mount will work themselves loose and sometimes fall out. I think I've had the dealer replace/tighten them at least three times since it happened the first time last year. I keep an eye on them and I can tighten the rear of the two bolts fairly easily through the wheel well with a ratcheting combo wrench but the front bolt is a pain. Not sure why they didn't just use threadlocker on them the first time they came loose. They said my truck is the only one they've seen with this issue.

 

Did they use thread locker this time?

 

Supposedly, but we shall see.

 

Hope so.