I’ve recently acquired a 99 LX auto with 221k miles. I’ve been driving it for about a month now and have noticed that when I accelerate and then let off the gas, the car will stay in gear and then I can visibly see it downshift (by watching the tach) down to first as i come to a stop. I’m not sure if this is related, but for a few days last week, I got a pending P1706 code. It was particularly cold those days. It has since warmed up and the code has gone away. Today, I did a drain and fill on the transmission and the fluid was very dirty.

So, is the P1706, neutral safety switch causing the issue or do I have a larger issue? I am not very versed in automatics, so any advice would be welcome.