Hi there,
Yes, you can remove the differential and service the output shaft seal from the transmission.
However, a few points for you.
#1, there was a seal revision because some of the older ones would take a set when the vehicle sat for an extended period of time. But once the vehicle was driven, it would reseal and not leak further until stored again.
#2, if you do not install the seal exactly straight, IT WILL LEAK AGAIN.
#3, the seal must be FLUSH with the rear casting.
The key with removing the differential is that you do NOT lower the driveline any more than is necessary. If you do lower the driveline too much, you will break parts on the rear of the engine or crack the firewall. Reference the diagram on the torque tube for correct lowering instructions.
Allthebest, c4c5