Weird noise

So I recently noticed a strange noise. When I first start up my truck and start driving down the street I get in second gear and just lightly cruising down the street I hear a strange click or engaging noise just 1 time. It seems to come from under the gas pedal and I think I can feel it in the gas pedal. I rolled the windows down and couldn't hear it outside. It only happens once when I first start driving and the truck drives completely normal. Any ideas? Is it just a normal sound? Am I being paranoid?

 

Might be the brake booster. If so its normal.

 

If it's right at 15 mph... normal.

 

Actually I think it is. Always slow speed. What is it?

 

Like anti lock brake system check or something. Mine actually doesn't make the sound but many many people have reported the same sound.

 

Thanks for the info. I can stop wondering and being paranoid now lol.