99-04 silverados(or 03) have full disc brakes. In 04/05 they got cheap and went to drumswat...?
Right if you guys ever drive a fullsize GM from those years youll notice the parking brake sucks from the factory, that shitty ass horseshow design brake shoe inside the drum never worked quite right. But weird part is they kept the disc brakes on the SUVs.I'm pretty sure the reason they stopped using drum rears are because they were having problems with the parking brake holding.