So my 2004 Jeep Wrangler with a 3inch lift vibrates on takeoff I have a half inch spacer above the transfer case skid plate. I am considering a SYE to the rear and possibly a CV driveshaft if that will help.
U joints on rear driveshaft are good
If it just does it when taking off, check your transmission mount for separation. Put a small pry bar between the back of the transfer case skid and the transfer case and pry up. If you can lift the tc, replace the mount.
What angles are your drive shaft joints at? A cheap protractor would give you (guestimate) angles. If the one ate the x-fer case is steep and the diff is ok. Your vibrations are always there (but only felt at low speeds).