Hello and welcome!
Just my 2 cents, don't have to be correct. Rule of thumb when you purchase a used 4x4, best to steadily invest in the following:
1- Change all the bushings (front and rear)
2- Check for play at the steering arms, ball joints, noise from the wheel bearings, get all the nipples greased heavily, change all the arms that require changing them (steering arm etc). I doubt your steering box will need to be changed, but its vital you do these things first and only then jump to other conclusions.
3- As for the sound, could be the drive shaft, the wheel bearings, or the gear itself.
4- Change all the lubes you can, engine oil, brake oil, diff oil, gear oil, 4x4 oil, clutch oil.
5- Change the clutch kit and accelerator cable.
6- Understand now that your life is screwed, and nothing will be cheap, live with it
Some times, you'll just have to go through the pain of the process of elimination. Best of luck!
PS. Do not use non-genuine parts, you'll only be in more trouble later on, TRUST ME!