I've got an 06 sienna 159k and I want to change the transmission fluid. It has a weird shift every so often completely random and sometimes has the down shift lag when taking off from a stoplight when not coming to a complete stop. The fluid is red but kind of dark. It was over filled by half a quart when I bought it the shop that did the work on it did some pretty crappy stuff like they just didn't know what they were doing I've had to fix several of there things so far. I sucked out half a quart and it seemed to do better but still not completely smooth. Should I drop the pan and change the filter? And should I swap out all the fluid through the cooler lines for a different kind of fluid? I highly doubt it has type iv in there right now but it's definitely not maxlife I know the smell of that stuff a mile away. My dad used the Walmart supertech Mercon LV fluid in his and it seemed to do okay but i also never drove it so it may still have had the same issues as mine and he just never said anything. Would castrol transmax import multi vehicle be a better choice? I know maxlife says it's compatible but every transmission I've put it in hasn't taken it very well and I ended up switching back to OEM fluid. Only reason I haven't just gotten the OEM fluid is because the dealer is currently out of stock and I would like to get fresh fluid in there before I start towing and I was wondering if there is a better option out there.