Temp. gauge for 03 TJ

I am wanting to install a temp. gauge on my 03 TJ. Does the 42RLE have a test port in it anywhere? I have Googled this and everything I see is for the sensor to be mounted to the return line going to the transmission. This is also how B&W gauge says to install it. B&W also says it has to be mounted in a aluminum line so the sensor is grounded. I have seen another gauge that you screw into the test port. I think it would be easier to just screw the sensor into a test port if the 42RLE has one. If you used a "T" did you install it into the rubber line or the aluminum line? I'm not good with plumbing so if the transmission does not have a test port I would like to install it with a T with hose barbs on the rubber hose. If I install it on the rubber hose the sensor would not be grounded. What have some of you done?