I have just rebuilt and changed differential. (4.11 to 3.54 34 ford)
Diff. and all bearings new.
Is it normal for banjo to heat up after 4 or 5 mile trip?
Is there a break in routine recommended?
They will run warm but not so you can't lay the back of your hand on it.
One of the bearings may be set too tight.
Set up right, you should be able to go drive normally right away.