hi-i'm just lurking around from the 05+ tacoma forum. here's the thing-i'm sure you realize by now that you should have said something about the condition of the truck when you took delivery. with that being said, if the dealership is going to do the repair for you at no charge, you should just smile, nod, and let them do it. whether or no you did it going over a rock, driving down the freeway ( i believe you that you didn't) or an evil gremlin cracked it with a hammer and chisel in the middle of the night, it is not something that is warranty. oil pans do not just crack, something has to strike them-that is not a defective part, thus not warrantable. whether it was the person who did the dealer trade or someone at the store itself, toyota will not pay for it, they will reject the claim and tell the dealership to tell the customer to contact their insurance company.(toyota would assume the customer did it) anyway-----as i am sure that you did not yet get your customer satisfaction survey from toyota regarding your purchase, it may be in your best interest to go to the general manager of the store if service gives you any trouble with fixing it and let him know what's going on. those surveys mean a LOT to dealerships. they tell toyota how the dealership is doing and that affects what kind of treatment they receive from the factory. if he is a smart business man, he will bend over backwards to please you so you give him a favorable score on his report card.
good luck.