There is a special stepped cup that is needed to install the seals along with a long handle to beat on..
I had my 01 Ram done at a local shop, they did not put it in 4WD and they had a heck of time to replace the axle, they had to pull the CAD off and line it up...

I had to do it myself again becase they used non greasable joints.. I put it in 4WD and had no problems..

Excpect I have one seal leaking and have to take it apart again..