99 passat break down on highway

[skywalker070305]

After driving the car on the highway for about ten minutes the tempature guage went way up and the alarm came on so my wife pulled over to the break down lane. I opened the hood expecting to see coolant leaking but much to my surprise i saw transmission fluid.How would a transmission leak cause the engine to over heat like that?? I checked the engine oil and it was fine,coolant level was also fine. Its a V6 model with the triptronic tranny. I didn't get a chance to really look under the car to see were the leak is coming from, but even if i found the leak why would the engine over heat?? I'm puzzled.. If any one has some info to point me in the right direction it would be greatly apreciated..

[Will12]

Sometimes, the sensor goes bad too (mine is intermediate). Also, the water pumps has a plastic impeller which breaks off, dropping cooling fluid pressure, thus making the engine run hotter.

You can check the engine with temperature gun to see that it is at 190 degrees.