2004 toyota sienna, have had the transmission “reprogrammed” by the dealer three times. It always has and continues to shift down prematurely, while in cruise control, on grades that are easily pulled when not on cruise. I know that it probably doesn’t hurt anything, other than mileage slightly, but is a constant source of irritation for me. Is this a normal problem with this vehicle?
Love my Sienna. But, what you describe is so subjective that it is hard to address. One person might think it’s downshifting when it shouldn’t and another person won’t notice it. Compared to the Caravan I had previously, my Sienna seems to pull hills much better.