To check the trans actual running temp you would have to weld on a bung close to the top of the pan. Normally a probe is installed in the pressure check port just ahead of the shift shaft drivers side, 3/8" NPT plug there. To install a probe in the cooler lines require a tee being installed in the forward line, that checks the temp from the TC which will be a lot higher than pan temp. The engine temp probe can be installed on drivers side rear of head, there is a 1/2" NPT plug there.