[1948F-1Pickup]

Just thinking about doing that job the other day.
You'll have to remove the nut and pull the companion flange.
Regular puller for that job. Nut is 3/4-16 thread, 1 1/8" hex.
Since the pinion bearing preload is involved, I'd probably
mark the nut, pinon & companion flange before removing the nut.
R&R the seal and then everything in the reverse order.
There's a companion flange tool mentioned in the manual
to keep that item from turning while you torque the nut.
The nut gets torqued to 140-180. Theoretically, the marks
you placed on the nut and pinion should line up somewhere in
that torque range.