Transmission Temp Sending Unit Location

[Coupe]

Summers seem to be hotter than they were in 1972. Traffic is heavier, with a lot of stop and go, and stop and "wait."
I decided it would be a good idea to install a transmission cooler. I have completed the install and now would like to install a trans temp gauge. It's a 318 w/ 904.
I've heard different opinions about where to place the sending unit. Placing it at the converter, to read the actual trans temp, or "as the Autometer instructions advise" placing it on the return line to read the fluid temp going in to the trans.
Anyone have any advice about where the trans temp sending unit should go?

 

[hellrats]

In the return line. That is the what the temperature of the fluid is that is entering the lube circuit of the transmission.

 

[aussiemark]

I would just put the cooler in and not worry about a gauge it will just make you worry for no reason and the last thing you need is to rear end someone while checking the temp gauge. Put the trans in neutral if you have to wait a while that will help a little.

 

[Dodgeboy]

In the return line. That is the what the temperature of the fluid is that is entering the lube circuit of the transmission.

I bought a deep sump tranny pan that has a spot for a temp. sending unit, (& a drain plug) I use this for my gauge. I also have a external tranny cooler with a temp.sender switch to turn it on/off (currenty hooked up to a toggle switch). I have been thinking about installing the fan temp. switch in the drain plug as I have noticed that when the tranny pan is at 170°, the fluid going into the cooler is 140°, & 120° leaving the cooler. I was orginally going to mount the fan switch in the return line but with a 50° difference my fan would never come on (its on @ 180°/off @ 170°. I don't know if the pan just holds the fluid thats dripping off of the valve body? And its temp doesn't matter? Is this kind of a correct statement?