1. Raise the car and put it on stands.
2. Check the driveshafts. In the presence of dents, cracks and deformations a shaft replace.
3. If traces of a leak are found near the transfer case or gearbox (ov) replace seals.
4. Check by rotating the wheel for noise coming from the hinges.
5. Check the joint play by trying to rotate the flange and shaft in different directions. Any noticeable play indicates heavy wear on the hinges.
6. Check for grease leaks from under the sliding splines.
7. Check the serviceability of the axle shaft seals, leaks from the seals are visible from the back of the brake shield.