Originally Posted by cknsls
That chart posted at the beginning of the thread is at least 25 years old and has been making it's rounds around the Internet for at least that long. BTW-it was wrong then and is VERY WRONG now because it doesn't take in to account the leaps and bounds in the advancement of transmission fluids like the new Dexron 6 and other fluids speced by other auto manufacturers.
The Dex 6 is good up to 275 degrees and the Silverados with the new 6 speed transmissions will actually tell you (through the DIC) that it's getting too hot. The new fluids are well refined with the Dex6 actually refined so well it almost carries the same properties as synthetic fluids.
See advantages of Dexron 6 about half way down the page-
Dexron VI: Why we use it and why we DO NOT FLUSH OUR TRANSMISSIONS!
I totally agree with the chart being outdated; noted that to someone in another thread. Just had no idea what the fluid could withstand in regard to high temps.
However, that tech letter posted states in the heading "why we DO NOT FLUSH OUR TRANSMISSIONS!" and yet, they go onto describe how to correctly flush a transmission using (I'll assume Kent-Moore tool) J 45096.
I had my H3 trans flushed in Moab by the local dealer and he used a Kent Moore flushing tool that used Dex VI as the flushing agent. That went along with a neighbor of mine who was a GM trans engineer.