I have a 2007 I5 reg. cab SLE 4x4 I bought new. I only have 36,000 miles on it. I was looking under it the other day and noticed the front of the transmission pan was damp but not dripping. Took it to the dealer and they said it was wicking fluid around some of the bolts and so they replaced the filter and put a new gasket on and new fluid and all is well. But I said it didn't look red like transmission fluid but brown even though it looked like to me to that's what's where it was leaking. The mechanic told me that the fluid they use now from GM is actually a purplish color and turns that brown color when leaking. I sure didn't know that. I always thought you could tell the difference from transmission fluid and an oil leak by the color. But I guess not any more.