Transmission Retarder OverTemp

[davidbrady]

Ernie,

I find it nearly impossible to keep it below 230 deg F on a 6 percenter of any length. The fan turns on at around 230 deg so there's lot of thermal mass and resistance to climbing at that temp. I find it usually settles in a little above that temp in fourth gear. But there are some grades where you need more. Descending into Death Valley from the west is an example - something like an 8000' drop in just over 5 miles or so. There I hit 250 deg F but it didn't throw a code as it shouldn't. Coming down Eisenhower Pass east bound on I70 I had to descend at 35 mph to keep it at or below 230. I know today that I was babying it too much and I should have been able to descend at 40 to 45 mph. The transmission can easily handle 250 deg F. That's my new self imposed limit before getting on the service brakes, or attempting to let it cool down.