Jeep Repair: rear transmission seal, propeller shaft, slip yoke

Question
I am going to install the rear transmission seal on my 1996 jeep cherokee 6 cyl 4.0 rwd.  Do I tap the seal all the  way in till it no loner goes in or do I just tap it in till it is flush with the outer housing?  When I first had this seal replaced three years ago, it still had a small leak and I used it like that for three years. Recently it started leaking more so I took the seal out and ready to place it back.

Answer
YOKE SEAL REPLACEMENT - 2WD
REMOVAL
Raise vehicle.
Mark propeller shaft and axle yoke for alignment reference.
Disconnect and remove propeller shaft.
Remove old seal with Seal Remover C-3985-B from extension housing.
INSTALLATION
Place seal in position on extension housing.
Drive seal into extension housing with Seal Installer C-3995-A or C-3972
Carefully guide propeller shaft slip yoke into housing and onto output shaft splines. Align marks made at removal and connect propeller shaft to rear axle pinion yoke.
Removing Extension Housing Yoke Seal
Installing Extension Housing Yoke Seal