I installed a set of ISSPRO guages in my truck over the weekend and Notice the transmission temp was higher then I expected. I installed the sender in the "Hot Line" going from the transmission to the cooler on the block. While sitting in the drive thru I saw my temp guage go to 195+, even though it was 30* outside. I can only imagine what the temps will be in the summer when I tow my 9,000lb trailer when it's 100+ degrees out.

What temps are normal and safe?
(Remember-Sender is in the "Hot Line")

 

You'll see them drop. There's alot of friction going on when sitting still. It'll drop just as you take off driving.

 

Yea that's pretty normal. When you get back on the road and your TC locks up then you will see temps drop. I've had mine up to 240* breifly while climbing a steep hill with my 11k toyhauler, other than that it is usually in the 150-195 range, towing. Mine usually hangs around 195* in stop n go traffic here in Phx with outside temps in the 110's. This time of year mine doesn't seem to get above 130* on the highway.

 

I dont think i've seen mine above 130* lately, but I have mine installed in my mag-hytec trans pan, so I'll probably see lower numbers than yours. Like it was mentioned above just sitting around it will climb.