And researching a Caravan with the Mitsu 3.0L Manual Trans, it uses 5w30 also....
Put 80-90 in it, and you'll kill it!
And, given the warmer climate in this area, the 10w30 would generally hold up better. 5w30 is also recommended for the motor, but only in a climate where it will see temps below 0 Farenheit....