Johnny Dearborn wrote:
I was in second gear going up the Whitney Portal grade. Idling was actually the thing that set it off overheating. Once I stopped moving, it began to overheat and the fluid came pouring out.
What I should have done was keep driving as fast as I could even if it was around the campground. Unfortunately, at Whitney Portal, once you get to the top, there's no place to really go but down. I did the Lee Vining Canyon/Tioga Pass grade twice earlier that week without any problems. There at least there was enough time for the engine to cool down once I got to the top of the grade.
That Whiney Portal is a fairly long and steep climb. I wonder if you were lugging the driveline a bit when in second. If you have a tachometer I think you are looking for 3500 to 4200 rpm when you encounter such a grade. Possibly you would have been better to be in low gear at maybe 3500 rpm and 25 mph when climbing (estimated numbers).
More rpm means more air through the radiator, more air through the auxiliary cooler, more fluid flow, less heat from the torque converter.
Yes as you reached the top the fluid was already about boiling and as soon as you started to idle you had less cooling and the existing heat pushed the fluid over. If you do need to idle maybe keep the rpm up a bit in neutral/park for a couple minutes. (1400/1800 rpm)
I recommend the synthetic fluid for additional heat resistance.
FYI I read the grade steadily increases to 9% for the last 5 miles.
Beware of Nine Mile Canyon road to the south (395) just out of Pearsonville is a solid 9 miles of 10%. And if you detour to Death Valley there are several areas of long 8%/9% grades not to mention summer heat. Stopping immediately at the summit of Whitney Portal is a killer and hard to compare.
