T5 Five speed slant six 74 Dart Sport.

Is there any guesstimate of speed (or high speed DURATION) limitation with the 4.11 axle gears whem the final drive is roughly 2.8? Is there a necessity for higher frequency interval for axle maintenance (like drain/fill gear oil intervals) or concerns for bearings? Thank you. Thanks for all of your help and effort. I hope that you and Kitty are doing well!
Dumb it down for me brother.