I have my sending unit in the line going to the cooler.
This is a freshly rebuilt 4L80E and it seems to get hotter than the 60 did, but I had the sender in the pressure port on the old trans.

I'm seeing temps between 220 & 230. Granted it is over 90 deg here, and I've been doing some "spirited" driving, but it seems a little on the hot side, but I really don't know.
What temps are you guys seeing with the sender in the same place.
What temps should I see if I move the sender to the return line?

TIA

Craig

 

You have chosen the hottest spot to get a temp ready fom there is , Those numbers in that location are acceptable. ideal location however is the pan.

 

What would you say is the max temp I would want to see where the sender is?
Max safe temp for the pan?
What about the return line? That would be an easy move. I'd rather not drop the pan, it's got fresh fluid in it.

 

I have my sender in the same spot and my temps stay around 150-160 while cruising. In stop and go traffic with 95* weather, I get up to about 180-185. I run two coolers with a Yank SS4000.

I would think the return line would be a waste....you want to know how hot you get, not how cool.

 

The temps you are seeing where you have the sender located are acceptable . Cooler is better but if those are the highest temps your seeing I would not worry since the fluild being returned and in the pan would be considerably cooler. I do agree putting in the return line would not be a good idea since these would be the coolest temps in the circuit.

 

FWIW there's a great chart on my B&M trans cooler box. Around 280 Fahrenheit is where ATF begins to form varnish. So 260 degrees and above is a critical range and should be avoided.