Transmission oil temperature

[JeffreyP]

Not another ATF thread, I just want to see if this would work for measuring ATF temperature without spending money on the infrared thermometer or the like.
According to the ATF DIY article and recommendations, the ATF level measurement (in my case a 98-E320) must be done at 80Celsius. Here are my questions:

1. Doesn't the transmission line go through the radiator for cooling? If yes, then
2. should the ATF be at the same temperature as the engine coolant? So measure the coolant temp should be quite simple

I believe there is also a procedure using the "REST BUTTON" to see the coolant temperature? Does any one have the link?
Please let me know what your thought on this - Gilly, MBDoc and other informed mechanics?

Regards,
JeffreyP