Hello everyone. I am a long-time Acadia owner (since 2010), but new to this forum. Can anyone tell me what the best diagnostic tool to use for the Acadia? My check engine light just came on yesterday and my wife told me the transmission was slipping. I really want to see what the problem is myself before bringing it to a shop. I have already checked the fluid levels and they were good to go. The vehicle is a 2007 model with a little over 140k miles on it. The original transmission went out while the vehicle was still under warranty, so the transmission that's in it now is a refurbished one. It was installed around the 100k mile mark. Any advice on the best tool, or what might be the problem with the transmission would be greatly appreciated!