Good info in this thread so far, thanks much.
For what it's worth - I don't have much concern on the transmission temps - the 10sp in my work F-450 runs at 235 to 245 all the time (it's always towing or has a massive load on the flat bed). It's just over 150k miles and has been serviced at 50k...
I am looking for official information from Ford on the normal engine operating temperatures. My Ranger is basically in stock form - factory towing package, Fx4, extended cab. I do have the Ford Performance shocks/struts and upgraded leaf springs in the rear.
For example, I found this for the...