My dad has an a Loadall as well and to tell you the truth he hardly ever changed the oil and it ran well for many years. I know the Cat loader we have uses a Perkins diesel and I believe its every 250 hours.
Hi,
Skiman26 - A >CI-4 Plus 15W-40 HDEO is recommended here - Castrol, Delvac, Delo, Rotella etc. - they'll all perform at about the same level. We get such temps here too.
You're best to use UOAs to determine your best OCI for your operation