Transfer case shifter gap in floor.

[eighteenninetytwo]

Hi all, and a Merry Xmas.
I am pondering how to cover the gap in the transmission tunnel that the transfer case shifter goes through when I line the truck. The gap is about 2" wide and 5" long so a fair bit of noise comes through and also water could easily get thrown up there and soak the carpet when driving in wet conditions.

I have a new boot and ring for the shifter to go over the carpet but what do people do below the carpet to keep both noise and crap out?