Temperature gauge goes to hot when transmission is in gear?

First let me ask does the temperature gauge do both Transmission Temp and Coolant Temp?
The diagram you have shown is nothing like where my transmission dipstick looks like. The Ford manual does not recommend owners fiddle with the fluid changes and adding fluid. That never scared me! Its under the battery box after removal of all the air intake components. I have checked the fluid level and it is nearly at the bottom of the "hash" marks. I'm guessing it is down 3/4's of a quart if the full hash mark section represents 1 quart. I am having difficulty obtaining the Motorcraft CVT fluid. Everyone is out it seems. I know Ford's CVT transmission is a chain type and not a belt so it could be fluid sensitive and will definitely need the Motorcraft brand. However, the transmission is quiet and functions through all the gear shifts as it should. Additionally, my laser temp sensor shows the oil pan temp to be at about 125 degrees while the vehicle temp gauge is just about pegged at hot. Understand my wife never continues to drive when the gauge climbs to hot. She pulls over every time and will continue till we figure out what's up. In most all my research on the web I cannot find if and where the coolant temperature sensor is. All I find is a Cylinder Temperature Sensor located behind and under the intake manifold. I'm not sure if I can tackle that job if it requires me removing the intake and other goodies that might be required. If it is removing a cover and unplug and unscrew, that I can do.

I'm not an ASE mechanic but have worked on my own vehicles for 50 years, from changing out a 300 ci. Short block to clutch work and brakes and suspension work but I'm not sure I am explaining my situation correctly.

The gauge is reading hot, sometimes completely in the red but there is no indication the motor is overheating. It seems strange that the coolant was not boiling and even more strange that the temperature would return to normal in less than 5 minutes sitting on the roadside in some cases in under a minute. I don't think an overheating engine block could possibly cool that fast. When this first occurred the first thing, I checked was the cooling fans and they were both working fine. I changed the thermostat in case it was functioning intermittently, but the situation remains the same. I used my laser temperature gun to check temperatures in several areas on and around the engine block, radiator, water pump, Thermostat cover, CVT transmission cooler, oil pan and Transmission oil pan. Nothing reads a temperature over 191 degrees.

Okay, it's been a while since my last communication because I have been waiting for Transmission Fluid in the Mail. It arrived and I topped off the fluid. Additionally, I purchased a new Engine Coolant Temperature Sensor and installed it. However, the wires that connect to the sensor were in bad shape. (See the photo) I replaced the wires, plugs and all. Soldered to be sure of a good connection. Hoping this will solve my issue. I let the car warm up and test drove it. Once again at 35 to 40 the temperature rose to the hot line, and I pulled over and turned off the engine. I waited exactly 3 minutes and started the engine. The temperature gauge read normal put it in drive and in about a 3/4 of a mile the temperature again rose to the hot line. I waited 2 minutes this time and again the Temp was normal. I made it to my carport with the gauge at the hot line. I used my Infrared temperature gun on various engine parts Block, Heater Hoses, Water Pump, Intake Manifold Bolts and more and the hottest reading I got was 204 degrees. Most were 170 or below. So, what do you think is my next step? Would the Cylinder Temperature Sensor have anything to do with this issue?

My car is not overheating. Only the temperature gauge reads hot.

Using an infrared thermometer, I checked every aspect of the cooling system including the radiator. While the temperature gauge was almost in the red. No reading was above 191 degrees. If you read all the posts, you can see I’m really at a loss. Even at the ECT sensor it was 179.

Using an infrared thermometer I checked every aspect of the cooling system including the radiator. While the temperature gauge was almost in the red. No reading was above 191 degrees. If you read all the posts you can see I’m really at a loss. Even at the ECT sensor it was 179

Did that yesterday. Check my other posts and you will see a picture of the wires. They were bad but it didn’t fix that gauge issue.

One of the other things I failed to mention is that through all these issues there was never a check engine light and a code from the ECM. Still hasn't been one with continued use of the car. I found a website today that shows how to test the ECT sensor and another how to test the 5 volts from the ECM and the ground. I was able to test the sensor and it tested okay but my OBDII tester won't test Live voltage from the ECM.

If there is a short in the wires that go to the ECM, then why wouldn't the gauge either bury hot or not move at all when the car is started? It acts normally as the car warms up but then shoots up to hot running down the road.

At the most 180's.

Hello Ken, I have a couple of questions before I tackle your recommended test. Is it correct that I will need to remove the tire and the inner wheel well to access the CVT sensor plug? Will the transmission function if the CVT is unplugged?