up2nogood wrote:
wilber1 wrote:
Depends a lot on the location of the probe. If it is in the transmission outlet before it gets to the cooler, 240 pulling a grade with the torque converter unlocked or backing up a heavy trailer wouldn't be unusual, but it should cool down again very quickly once the converter locks up again if you have a good cooler. 240 anywhere else would be high.
Test port above the second transmission pan bolt from the front drivers side is where the sending unit needs to go. ATF goes from the pan thru the oil pump ,and then past this port. This location for the sender will give you pan oil temperature, or very close. Safe temperatures are anything below 200 ,200-225 is the warning , over 225 is too hot. Why do you want the temperature of the oil going to the cooler, what you want is the temperature of the oil getting pumped into the transmission ,not what it ends up coming out. Regardless it has worked well for me for 8 years of towing heavy ,and never seeing 200 .
I'm not familiar with the 4R100 so I will take your word for it. I agree that as far as transmission components go, you want to know the temperature of the oil in the transmission itself but the peak oil temperature will be when it leaves the torque converter.
If you are pulling up a steep grade with the torque converter unlocked or backing a heavy trailer up a slope, if you have an efficient cooler, the fluid temperature leaving the torque converter can easily be above 250 even though the pan temp is much lower. This gives me a problem with charts that say you should be changing fluid every 6,000 miles if your fluid temp goes over 250. If that's the case, everyone towing in mountains that don't have torque converters that lock in lower gears should be changing fluid every 6K. I don't think so.
