This seal keeps popping off by itself. I tapped it back in, and it came out, same thing over and over again. I have a new seal coming from NAPA tomorrow, but can't figure out why it is coming out to begin with, and whether or not the new seal will fix it. Does this seal need to go in a certain direction (it's got that little tab in the bottom there???????)

 

My NV5600 seal on my 04 3500 started doing this. I tried 2 new seals and a 400$ tail shaft nothing worked. A local shop drilled a hole above and below and installed two pop rivets. Still holding after 60,000 when I sold it. Your mileage may vary.

 

I should add you drill the caseing so the edge of the rivets just grab the seal ring...