Trans Temp vs. Ambient Temp
 

Just a quick question regarding transmission temp. and its relationship to ambient temp. I have had my trans temp guage in now for a little over a year and I keep an eye on it pretty regularly. In normal driving back and forth to work I cover both city and freeways, most of which is freeway. I normally hover right at the low side of 170-180. This summer it has been excessively hot and humid here (90-100 degrees and humid for SoCal) and I have been seeing temps running regularly from the high side of 180-190. Is this about right? I ask because I really started noticing the temp increase right after I had the dealership drain the fluid and install a Mag Hy-Tech pan. I checked the fluid and it is full and clean so I'm hoping that its just the change in the weather. Thanks.

Mine reads the same. About 95+ and its around 190, under that in ambient and its around 170. In the winter it won't break 160 in normal driving conditions.

My temps track ambient very closely. I've often wondered what got into my tranny only to look up at the overhead and notice the ambients are over 100. Oddly I have not seen as big a variation in cool line temps as I did on the internal and hot lines.

see https://www.dieseltruckresource.com/...d.php?t=213836 for my question about that. Bottom line on that is the sensor location can make a HUGE (eg 80 degree) difference...