Most pinions i have ever done on dana axles are 3-8” lbs I actually have a torque wrench (screwdriver)  that sensitive, but many use “feel”

Bearing preloadcalculator

i think a lotta guys go by feel, if its tight to begin with thats not good, bearing load and shaft play are of course two diff things, some depends on gear type too, that straight gear is going to need less end/shaft/gear play - straight gears are less forgiving than slanted/conical type because you have less metal engaged from the get go

Bearing preloadSKF

Your shaft requires slight preload as cones are outside races. As shaft warms the longer it gets and the bearings get looser. The longer the shaft. The more preload necessary. If cones are inside the races. No preload needed as bearings get tighter as shaft warms. Quite often these require end play. Again the longer the shaft the more end play.

I’ve never rebuilt a gearbox for a rotary mower. The bearings on the lower shaft are tapered bearings like a wheel bearing. Should I try to tighten them until there is some rotational drag like a wheel bearing? Or just enough to take the play out of the shaft? The box goes on a 315 bat wing bush hog that is probably 50 years old. Thanks for all replies.