Adding Tranny gauge - what size lines or port?

[TeryT]

I'm adding a tranny temp gauge to my 4R & need to know the size of tranny cooler lines. The NAPA guy said he didn't have a clue as to what size was used on one of them ferin makes, just that it wasn't SAE (duh).

Also wondering what size the tranny port is if anyone knows. This would be my 2nd choice for placement of the sensor.

In either case, I'll have to make up an adapter, as the sensor comes with a 1/8" male pipe thread.

Thanks!