Jeep Transfer case drop? What is it? It's the most inexpensive solution to eliminate the drive shaft vibrations from too much suspension lift.
When you lift a Wrangler "too much" it puts the drive shaft / U-joints in an excessive angle. That excessive angle makes the U-joints bind up causing a vibrations
I had driveshaft vibrations from doing the junkyard lift. I'll put links below to the YouTube videos for the lift. When I test drove the Jeep after the lift, as soon as I got about 30 MPH I knew something had to be done. I felt like I was riding in a paint shaker! BAD vibration emitting from the driveshaft shaking the whole Jeep! I didn't want to put money into a slip yoke eliminator kit and the new driveshaft to go with it. With all my financial commitments I had at that time, shelling out that kinda dough wasn't in the cards at all!
It wasn't expensive at all to remedy this little issue. You can buy the actual kit (I'll drop a link below to the kit) or do as I did, go to the hardware store and get the needed hardware.