We recently dropped $7K on a new transmission and 2 months later it's bad again. This time the dealership says the culprit is a transmission cooler, causing coolant to mix with the transmission fluid- ruining the transmission and voiding the warranty. I'm trying to find TSBs to show that the oil cooler was probably the original culprit and should have been checked when they put the 1st tranny in, but can only find related oil cooler TSBs for the 3rd gen. siennas. Any advice or help out there for me? THANKS!!!!!!