My diff is from an S4 TII - the pinion seal is leaking like a **** + I need to change it out.

I bought a new pinion seal, crush tube + bearing. After looking in the FSM, I realized that I need more than one bearing now.

But anyways, can I do this with the diff still on the car? Or do I need to pull it again? Has anyone done this? Is it as easy as unbolting the flange, taking out the old seal, putting the new one on then putting the flange back on + re-torquing it to what it was before?