Ming, I don't think that the transmission is the only part of this minivan that isn't modern!
I'll admit that I have a hard time tempering my distaste of GM's minivans, so I apologize in advance for the toxic nature of this post.
More often than not, I'm pleased with the direction that GM's products of late are taking, but their approach to the minivan market is just plain sad. I can't think of a single way in which the Terraza and Relay (and presumably the upcoming Uplander and Montana SV6) unequivocally surpass their competitors. The CSV designation and design philosophy simply camouflage a malnourished minivan strategy.
And to defend these vehicles by saying that "they're alright" or "not that bad" (opinions with which I take no exception, incidentally) proves the point that at the end of the day, GM's effort on these minivans was weak. They'll get you from point A to B, and they're not horribly offensive to look at. But their competitors (DCX, Honda, Toyota, Nissan) do that, too, but with *arguably* greater versatility, technology, style, function, reliability (Honda and Toyota), and comparably-equipped value (Honda, Toyota, and Nissan).
It's frustrating to think that the monies spent on creating 4 different variations of this minivan (let's be frank, they're minivans, and nothing else) and the marketing it will take to move all 4 siblings could have been focused on making one, single memorable minivan. Both strategies have at least equal chances of insuring that Doraville builds 250,000 vehicles per annum. The only difference is now GM will be building 4 decent [and forgettable] vehicles at a time when having a good quality product in the auto industry is not enough to secure longterm viability. You would think that after 25 years GM would have picked up on that painfully obvious fact!
In the end, these 4 vans are definitely not "gotta have."