1997 4Runner-147k: Check Engine Code P1700? Which sensor?

Sorry in advance for the lengthy post. I just want to be very thorough in my description for those kind enough to help out.

About 6 months ago my check engine soon light came on. I got it checked out and was told that it was a sensor of sort(P1700)s. The guy reset it and told me to keep an eye on it, if it comes back on, get ready to change it. The light stayed off for about 4 months and I didn't have any problems with my vehicle.

Now, the light goes on and off and IT TAKES A HIGHER RPM TO SWITCH GEARS. It's running quite sluggish, but the problem isn't as bad when the light is OFF, as opposed to it being ON. Odd?

I can't seem to find out which sensor it is that I need because I can't find what exactly that P1700 code is for, other than "transmission".

I've heard that the sensor is easy to change as it is just one 10mm nut that you have to take out to replace it, I'm just not sure which sensor I need as I think there are two of them side by side? Speed sensor and something else I believe?

Can anyone please tell me which sensor this is or which ones it could be so I can narrow it down and try making this change myself instead of paying someone $300-$400 to fix something so simple?

Also, could there be something else wrong as well? My transmission isn't hard-shifting or slipping really, just the high RMP's to switch gears.


Thank you very, very much for your time and help to all of those who help out everyone on here.