Good Morning all,

I am looking for a little help/advice.

I am currently driving a 2014 XLT 4x4 Super Crew 5.0/V8. I am at around 78,200 miles on it.
I have noticed that I am hearing what sounds like a grinding noise (kind of hard to explain) when the truck is both accelerating and decelerating in the 1st and 2nd gears. I cannot determine where it is coming from. In 3rd gear or higher I do not hear the noise. Also, when decelerating I hear it but when coasting, not when braking.

Timing Belt?
Transmission?
IEW?

I will admit that I really do not know much about vehicles and wanted some help/advice before I take it in.
Also, would you recommend taking it into the dealer or not?

All Help/Advice is Much Appreciated.