So, only two years after getting the transmission and t-case from H8PVMNT, I finally did a transmission swap. After a lot of thinking I decided to get a rebuilt W56 from Marlin and run the transfer case as-is. Since it's a W56 having the W56 t-case was a big help.
First step was to take an old floor jack with the swivel-y thing missing and build a transmission jack attachment. Welders are great
Second step was to drop the G52, which happened without issue. Next I bolted H8PVMNT's transfer case and bell housing to the W56 and put them in. Again without issue.
The W56/4.70 transfer case is so nice after that grungy old G52. The shift boots were torn and useless and water had got in, making a bit of rust. Plus the G52 shifted soo sloppy by comparison and got burning hot at highway speeds.
Then I took it for a test drive... The new transmission is so much quieter, and shifts so much nicer, it feels kind of like driving a sports car
. Except thanks to the transfer case the sports car turns into a tractor on command.