Lost front wheel drive 2006 ck25

[Leonard malone]

I recently changed the gear oil in the front differential using spec oil. After it started to leak out around the shaft seal. I didn't notice until the front wheel drive stoped working. I'm not sure how much damage has been done. Before I take it apart I thought I would check on new parts, cost and availability. I was told by the local dealer that bevel case gear wasn't available. Anyone have any idea where I might look? Thanks,