I talked to Tech Help at Auto Meter where the guy gave me rough measurements. Measurement from bottom of thread to end of sensor probe is 1/2". I'm hoping the Mitsu temp switch is 1/8" BSP(JIS), if so I may be able to thread in the 1/8 NPT but usually the factory threads are fairly precise so I probably will have to run a 1/8 NPT tap. The most accurate measurement of A/T temp is at torque converter so if it's possible I'll see if I can use the factory port.

92 Montero LS 3.0L V6 Auto, Stock, Original owner, 185,800K miles