IIRC the OEM factory high oil temp alarm is 250* on my RAM
Hard pulls, high air temp and long grades I've never seen temps over 215*F
Had OEM alarm once backing 5'vr up long steep driveway...gauge reading 245*F
Found this on another forum.......posted back in 2011
Maximum transmission temperature
In the February 2011 issue of Trailer Life magazine RV Clinic in response to a reader about the maximum transmission temperature allowed in a 2009 Chevy Silverado, the Tech Team had this response.
“General Motors’ in-house towing team expert provided RV Clinic with this statement: The maximum allowable automatic transmission fluid temperature is dictated by the transmission oil itself. The oil begins to degrade significantly above 270 degrees Fahrenheit, so we design vehicles so that in all but the most extreme conditions, the fluid temperature in the transmission sump stays below 270 degrees F.
We allow for up to 285 degrees F in extreme conditions (i.e. towing a trailer with combination loaded at GCWR in Death Valley). But for customer usage anywhere else in the country, even at GCWR, transmission sump temperature should stay well below 270 degrees F. Above this point, certain internal components, such as seals, begin to disintegrate rather quickly. Although newer synthetic fluids can withstand higher temperatures we still recommend this (270F) as a maximum temperature. "
And this also was posted.....
a little research thinking that maybe GM was referring to new vehicles that are utilizing synthetic oil as all GM trucks do since GMT 900 in 2007 (much higher operating temps than traditional "dino" oil). I found that transmission oil starts breaking down prematurely at temps above 175, damage occurs above 300 to internal transmission components, and as high as 275 is allowable for all transmission fluids. However, it you run temps above 175 (as we all do towing our rigs) more frequent fluid and filter changes are required as outlined in the following chart (validated from a couple of sources):
175 degrees change every 100,000 miles
195 degrees change every 50,000 miles
215 degrees change every 25,000 miles
235 degrees change every 12,500 miles
255 degrees change every 6,520 miles
275 degrees change every 3,125 miles
