My truck makes a clunking noise and shake violently
 

So my truck started making this little clinking noise when I shift to reverse, yesterday as I accelerated from the stop light it sounded like something broke like the clunking but this was louder and now the truck shakes so bad at about 15 to 20 mph. I'm good with fixing trucks, has anyone had the same issue. I saw some things that said motor mount or transmission mount. Are those hard to perform? Any guidance would be much appreciated.

Is it a 4 wheel drive?
Is it a crew cab and have a double cardan front U joint on the rear shaft?
That is what to check first
Check for a broken trans to transfer case adapter
Check the centering ball and yoke on the rear driveline at the double cardan CV joint

It would help if you at least establish a baseline of information about your truck... What year/model/engine/transmission/mileage. 2wd/4wd ?
Any other major events/repairs recently?