While doing research on changing my transmission oil, I came across this and thought it was interesting: From the FTE forum
https://www.ford-trucks.com/forums/member.php?u=23422
When I was at Ford we supplied transmissions to an off road race team. We won the Baja 1000 several times, along with many other races, and several championships. Over the years we went from E4OD to 4R100 to 5R110. With the E4OD and 4R100 we ran Mobil 1.
One race (with a 4R100 in the truck) the cooling fans for the trans coolers failed. The coolers were in the truck bed right behind the cab. They were there to protect them from debris getting kicked up. Without the fans they had almost zero airflow.
We were in the lead, but not by a lot. The trans temp gauge was pegged at 320F for hundreds of miles. If we stopped to change the fans we'd be far down the standings with no chance to recover. So the decision was made to keep going and hope for the best.
We won the race. The truck had no further problems, just the pegged temperature gauge. After every race we would get the trans back and tear it down. We were not only supporting the race team, we were testing prototype parts. This was a high performance durability test for us.
The Mobil 1 was dark, and a bit smelly. It wasn't black goo by any means. The teadown showed the normal wear we'd see after a race, but no damage. Except to all of the solenoids. The solder had melted off the solenoids and was laying in the bottom of the pan!
We don't know how hot that trans got. But we do know that the melting point of solder is
450F. So we know the trans was hotter than 450F
AND IT LIVED!
So when people tell me they damaged their trans because it got to 200F, or 230F, or even 250F, I know they are wrong. And that Mobil 1 is a superior fluid!