I have an early 03 with 190k on it. According to the previous owner the trans has never been rebuilt, only flushes which I have a stack of receipts for. The other day the truck was acting like it was searching for gears then it acted like it was in neutral. I got it to the side of the road and checked the trans fluid and it was high and full of all kinds of gunk plus what looked like water or condensation. The fluid itself still looked good though. It had not mixed with the contaminants. Long story short , had it towed to a mechanic friend that I have known for 20+ years. He said the trans cooler developed a leak and let coolant into the transmission. Is this a common problem? My dad talked to him not me so I am going to see him in the morn to get more info. Truck is bone stock, I have owned it since Jan '11 with 157K on it when I bought it.

 

Yes, it has happened before. It not very common but does happen. It is the cooler that is mounted to the side of the block and runs to this before the cooler up front. I forget the technical name for it.