Keep close track of the fluid levels in your transmission and rear end. If the seal on your drive shaft is bad more oil could pass to the rear end. Your manual will give you the correct fluid levels.
You may also upset the gaskets on your torque tube ball area by changing the angle of the drive shaft to the transmission causing fluid leaks in that area. The following is a past post covering that topic.
Torque tube gaskets You should also take off your rear brake drums to see if the rear seals are in good condition. Any sign of oil contamination will be magnified if there is a higher fluid level in the rear end.
Good luck, Mike
P.S. I would tend to be more cautious if I did not know the history of my transmission, drive shaft, and rear end components. Mechanically, you should not have any problems, but before you do anything I would take a long ride to make sure I felt no vibration in the drive train, braking inconsistencies, shifting problems, tire performance, unusual noises, etc. I would do this so I would not blame one of these problems on your new set up!!!