We just received a C-130 from another unit who had already performed the carbon fiber brake TCTO. (This is our only modified aircraft) The first time we towed the aircraft, all four main tires are making an unusual popping noise like loud popcorn popping. If you put your hand on the the transducer cap you can feel it as if someone was on the other side hitting it with a ball peen hammer. First I axle jacked each wheel and spun them by hand, but couldn't duplicate the noise. I removed all the tires, inspected the brakes and wheels and replaced the bearings and hardware. It still makes the noise. Anyone ever encounter this?