Tap Into Stock Transmission Temp Sensor for a Gauge?

I want to put a transmission temp gauge in but I don't want to drill into the fluid pan. I looked at a few diagrams and am left wondering why can't I just tap into the stock temp sensors with an after market gauge? Anybody know why I couldn't do this? I still need to do some more research on the schematics, but will somebody with sensor knowledge look at these pdf. Maybe we can find a way get a gauge without having to buy a full kit.

EDIT:
oops, I uploaded the wrong diagrams for this. turns out the temp sensors are completely inside this tranny. fuckle

 

It will be hard to find a aftermarket gauge that reads the stock sender. I am sure the sender resistance it not standard for aftermarket gauge companies such as Auto Meter.

I think your best bet is to add a T into the line running to the oil cooler.3

 

At this point I've pretty much looked at all options: inline, fluid pan, data reader (dashhawk, scangauge, interceptor) and one other cooler line variation using heat transfer. Just thought I'd try and come up with something new... but there's probably a reason nobody has done this yet lol. THANKS!