I happened to have a used snap ring out of a spare transfer case I had so I put that in.
But the actual fix is to install a transfer case saver. Basically it’s a lot thicker of a device with screws that hold it down, it’ll never break or fall off again.
Here’s a link to one off a quick google search:
Order a QK2069 transfer case saver kit at Torque King. Our transfer case saver kits are for the 231 & 241 NP transfer case with a two-piece tailshaft.. Shop for new QK2069 transfer case saver kits today.
torqueking.com
Good luck!