What is your transmission temperature

I guess my RV runs a little hotter than everyone elses. My RV is 37' and weighs about 19,000 lbs, has a 460 and E4OD transmission. I have not started towing yet, but I did add a temperature gauge and plum it into the test port on the side of the transmission. The RV has the in radiator cooler and a factory external cooler. I've also changed the tranny fluid, but didn't use synthetic (not yet). My gauge shows around 210 to 215 on normal roads or even up hills. This is after about a half hour of driving. It stays there the rest of the time. I did add an electric fan to the external cooler. It does not seem to help on the freeway but does help in traffic.

I've been concerned about this temperature for awhile and was wondering if I should switch to synthetic fluid and a bigger external tranny cooler. Any thoughts.

Thanks.