"He did say that the seal has to come from Big Dog"
I had a similar problem when I installed the Baker Open Drive. When I call Baker they gave part number, but would not sell me the seals. I went to the dealer and gave them the part Numbers that Baker gave me to repair the leak.
0480872#22 o-ring for main shaft
10705-02499 Large, Primary o-ring
3138-DSSC Main shaft shim for clutch
120-DD6R Main shaft seal
121-DD6R countershaft seal
Their (Baker's) advice was to replace both seals and both O-rings along with the main shaft shim. The dealer took care of it under warranty even though I replaced the primary myself. :2thumbs:
Good Luck
Carlos