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?

Your back brakes didn't lock up, your drive train did. Something broke in your transmission possible due to low lube or just age.

Alright. Thank you.