timken axle

I have a 1948 Truck with the Timken spiral bevel rear end (clamshell) that is leaking at the pinion seal. I have searched threads and found some with some good info on rebuilds, howeve,r not specifically on changing the pinion seal. My first question is do you have to pull the cover to change...

My 1951 Willys pickup has a very rough Timken rear axle and I'm buying a Dana 44 from a wagon to install... I know the hubs will be different... but I have new drums, shoes, cylinders, backing plates, etc already on my Timken axle... I think these are all the same... what do I need to change on...