bziggy

I Know this is been around and around but i have a question that i hope someone will answer. I have the temp sending unit in the test port for pressur on a 48re trans to get the reading for thr gauge. Now I have been told that this is the best place for the sending unit on the 48re and it is not the same as the 47 re trans in which it is a bad thing to put the sending unit in the test port. Can any one tell me what the diffrence is in the two trans that one is ok 48re and the other is not 47re? When i hooked up my modis computer it give the same temp reding on the gauge as the computer. I would think that is maks it a good location. If not could some one tell me the line size on the cooler line i think it is 1/2" and will try to make my own t-fitting.