u pull the drive shaft (on mine I can just wire it up to the cross member to keep it out of the way ,, mind the u-joint doesn't fall out) at the axle remove the pinion nut and u joint yoke then
R&R the seal
at least at my best recollection lol but you don't need to remove tires
you just need to get to the pinion nut and then to the seal .
risco is correct it is possible but not common
Edit this truck is easier than my procedure above since the ujoint and yoke don't need to be separated they are bolted on with 4 bolts just make sure to set your brake and chock the wheels