I was leaving work last night and suddenly I hear a pop then a loud whinning sound coming from the transmission and when the truck is moving it feels like the parking break is on. I circled around the lot and came back to a parking space to check things out. now the truck has lost reverse and is even making a slight whine while its in park. The fluid seemed ok. Do you guys think I'm looking at a rebuild? and if so what could be done to build it a little tougher? I've never had much transmission problems so I still don't know much about them.