Seems like boondocking is the way to go during covid. Went several miles on rough, washboard NFS roads to our campsite. Kept it in four wheel high until we were back on the highway after, then back to...
I’m not sure extreme vibration means the same to all of us.
Any way, if it’s what I’m thinking, I don’t think it is related to the TC being on or the road being traveled. What happens if the 4x4 is engaged on normal roads? Is it easily going in/out of 4 wheel drive? How many miles are on the truck?
Seems like it could be worn suspension components, transmission, or transfer case components. Good luck.