Transmission Temp Sensor

[butt]

Hey guys. Not a hard question but I have no clue where the transmission temperature sensor is on my '97 C1500 4.3. I was troubleshooting with autozone troubleshooter (don't laugh) and I am supposed to check for a faulty tts or tts circuit. That's another thing, how do I test or should I just replace because it is probably an inexpensive item. After all that, let me tell you what I am experiencing. While accelerating, the transmission will delay thru all gears. I get a lot of rmp's but no torque. I guess slipping would be a better term. The truck has 91k miles. I plan on draining the fluid and refilling and replacing filter and gasket. My Haynes book said to check for coolant. How can I tell it there is coolant in my trans fluid. Hope this is enough info to get you started and a great big thank you in advance. Jae