You can "add" a drain plug to your existing pan, for cheap.
Check out B&M plug kit #80250; can be found all over the net.
I installed one in my old Taurus pan. Actually installed it low on the sidewall of the pan, away from any internal obstructions. Put in on the "back" side so that when the front end of the car was up in the air, the bulk of the fluid would drain out the back. I put it on the sidewall because the Taurus was low slung and I was concerned about putting it on the bottom; the Silvarado may not have such concerns. But the sidewall system drained probably 99.9% of the fluid when the front was lifted enough for me to get under it.
Very effective; very cheap; never,ever leaked; easy to install if you can drill a hole and turn a wrench.