I cannot offer you my old water pump, but just some advice: sounds like you got a fwd 4ac water pump. They do not have a thrust bearing, and cannot take the loading of the fan when used in rwd. Tho they are also shorter in the snout so it should have set warning bells off when you fitted it.
Still, 3 months from Toyota, I'd go have a POLITE word with them and ask WTF???
If all else fails, an electric water pump will do an awesome job, if costing more than 1/2 of what i paid for my first 4ag inc loom and computer