Speed Sensor Problems

Good morning everyone,

Had check engine light, on my 1994 Toyota Camry 1MZ. Codes 500, and 720. Autozone said speed sensor, so I replaced it (after ordering the wrong part several times, has a 95 transmission). The same problem still persists, threw check engine light again(had battery disconnected while replacing sensor) and blinks the O/D, shift problems, sticking in 2nd, first. I assume the same codes but it has not been confirmed. If it is the same codes indicating speed sensor, what else could be the problem, and how should I go about diagnosing it? I should mention that at one point the check engine light was still on, but the O/D light stopped blinking and it shifted perfectly the day before I got the right sensor. I drove it after I installed the new sensor, worked fine but I wanted to "test it." and floored it for a bit(me likey the V6) and it threw the CEL and O/D blinking when I stopped to turn at the stopsign before my house.

Thanks in advance,
Jonathan

P.S. I should also mention that I have seen no issues at all with the speedometer, which I thought usually come with vehicle speed sensor problems.