I posted last year about replacing the transfer case output seal on my 2000 Tahoe and thanks to you guys, it was a pretty simple process. I did check it for several months after to make sure it wasn't leaking and all was fine. This weekend, I just happened to look under the truck and noticed some grease buildup on the frame and tracked it back to that seal. I could see a little drop between the rubber and the flange (rather than between the flange and the transfer case) so it looks like the seal is leaking again. Since I replaced all of the fluid last year, do I need to drain the transfer case fluid to change this again? I am not sure if it will just come pouring out when I remove the shaft, or if the fluid is elsewhere inside. Also, any tips on hammering the seal in? I remember last time, I found some blocks of wood and cut a whole the size of the seal in it and put it over the seal and hammered the block. Any better methods? Thank you.