IMO, 302F is way beyond the safe point for ATF. Even Ford Super Duties (4R100) are not supposed to go past ~220, but frequently run 190-210. To me, that's hot.
My FZJ-80 never saw any temps above 180, even when towing in Omaha at 106F ambient temps. It normally ran at 140F.
The temp at which the 'AT Hot' light comes on in Toyotas (including FJ62s) is super high and to me, far beyond reasonable (if it's the sump fluid temp). If my ATF got anywhere near that temp, I'd immediately do a fluid change and add a big cooler. YMMV.
Steve H. - KE0KNH
Colo Springs, CO
'78 FJ40, '89 FJ62, '98 4Runner