the anti lock brake system was stopping me from stopping at or around 5 mph. looks like the abs system. who puts the abs brake module under the truck. oh chevy. the module was all covered with oxide. try taking the brake lines off the module!.the solution was to grind the heads off the module mounting screws.(the torx scews heads were rivoted so you can't get them off).cleaned around the area so you can lift off the module. covered the base before i used vice grips to remove the rest of the screws. replaced the module with a rebuilt one