To recede means to move back or further away, or to gradually diminish. In this sentence, it just means that the sound of the truck got gradually quieter as it drove away.

Recede = back away, fade away, move back. It has the connotation that something is backing off slowly, smoothly, or gradually. So if the sound of the truck receded into the distance, another way to say this is: "the sound of the truck gradually faded away into the distance" Here, "into the distance" is where the "sound" is moving into, receding into. Hope that helps!