I started hearing a creaking noise at the back of my truck when stoping I thought it was the brakes because I only hear it when I'm stopping so I go to jack the truck up n I hear the noise that I thought was my brakes but now I'm thinking that it's something else but I can't tell what it is any ideas what it could be

 

Could be the leafsprings making the noise, either where the bolt goes through them holding them to the frame or from in bteween the springs themselves. I'd squirt some teflon type lubricant in there. Spray liberally so it penetrates the cracks. DOn't use penetrating oil. That could make things worse.

 

could be a ujoint creeking..