Cracked transfer case

[autoque]

The service center was replacing the transmission mount which is connected to the transfer case. When the transfer case was brought down, the aluminum case had a few cracks on the outside and some even chipped off when the rubber mount was removed. Dealer says it'll only get worse and worst case scenario is the whole case falling off and crippling the vehicle. Replacement is the only option available. They are asking for over $3,000. The rubber mount also has a crack but it's replaceable. Should I just drive the car or replace it? I initially told them to just install it back with the new mount, but they told me to reconsider. Why on earth the case would break in the first place is beyond me. I have pictures they sent me, as I was not at the service center.