Do a search
You can put the sender into the trans pressure test port - search posts by Byrd91 I think hes the one who pointed it out. You will need a spacer so it will fit, but do a search and it should turn up.
Good Luck.
I mounted my 2 1/16" Autometer gauge under the dash in a gage cup- a very simple install. Easy to see and out of the way.
I wire from the sender to gauge, one from power for the gauge, and then a ground and a dimmer circuit lead for the light. - also very simple.