There should be a light in the speedo when it's in emergency drive.
If you've got no front driveshaft you need to be in emergency drive or you'll burn up the clutches in the transfer case, I'm surprised it moves at all, the quadratrac is just a limited slip that can be locked, no idea about how it could be a 60/40 torque split given what's in there
It's a very simple vacuum operated system which can normally be solved by checking / replacing the vacuum soft lines.
I'd start by putting the driveshaft back on as it was never really designed to be two wheel drive, and see what happens
This is most of what you need to know
http://www.jubileejeeps.org/quadratrac/