Chev truck problems? Rear diff?

I have a 91 chev 1/2ton reg cab short box. I just replace the idle sensor cause it was stalling out when idling and starting. Then I went over a series of pothole. Right after when I was braking there was an really loud bang. I then noticed my park brake light came on. However the light shut off next time I pressing the brake. Following that I took a look around the truck and saw nothing loose or leaking. I then drove my truck to work and it seems to have no lasting issues. What happened? What should I do? Could it be a diff issue or tranny?