I have a '83 nissan 4x4 king cab pick up and the transmission just was killed. It happened in the morning on my way to school. I shifted into second gear and the back brakes locked up and it felt like the engine and tranny dropped which i found out they didn't drop. I pulled over and my truck smelled like hot brakes and were smoking. I saw a puddle under the truck and I found out it was my tranny. It has a huge crack in it. Any reason for this?