I recently acquired a 1994 Chevy S10 Blazer 4 door 4x4 automatic. I bought it from a friend for $400, knowing that it had a transmission problem. He says he was driving in the rain trying to "drift around corners", and running the thing really hard. He got home and realized reverse stopped working. Basically it shifts fine through all gears, but when it's put in reverse, the reverse lights come on, the engine RPMs drop, but it just stays neutral. Also, the "PRND12" marker is off. P is park, in between P and R is "reverse", but then R is neutral, N is drive, D is 1st, and so on. So I don't know much about transmissions. Could the linkage be off? From what I've worked with in the past, if the linkage is off, there's no park. Or is the reverse gear shot? The fluid is burnt and low, but I didn't bother changing it in case I definitely need a rebuild. It hasn't even slipped into reverse since the incident, just no reverse at all. Before the "Tokyo drifting" reverse worked fine

 

Linkage could be off just enough to cause these issues, but low/burnt fluid can cause this as well. I would start by changing the fluid and fixing the linkage.