Does anyone know what is a “normal” range for the transmission temperature?
I have a 2015 Ford Expedition Limited 4x4 with the factory HD tow package. I do not tow.
The vehicle owner’s manual does not provide information on what is the acceptable range of temperature.
There really isn't a minimum temp for tranny fluid, as long as it can flow. The high temp end gets a bit more complex. Normally (whatever that is defined as), tranny fluid operating temp would be 170F - <220F.
The variables that contribute to fluid temp are numerous, but mostly ambient air temp and load.
Once you get into that 220-225F band, then you need to consider that the fluid will degrade much faster, and that the higher the temp, the faster it will degrade (often referred to as 'burning it'). If you ever see your tranny temp above 230-240F, do yourself a favor and change the fluid soon.
Here's a chart that sorta shows that (be wary....the mileage scale is not linear):
http://www.txchange.com/heatchrt.jpg
