You checked your diff oils?
Simple task that can save you a lot of money, and warn you if any problems are starting to occur. The photo’s below show what can happen if you don’t, the problem was the axle seal was leaking but rather then checking under the vehicle after any off-road excursions to see if any damage had happened. (Not just axle seals) The guy kept on using the vehicle so every time it was driven into any water it was being forced into the diff housing, along with the grit & mud that was in the water, and over a period of time this is the end result.
As the diff cover was removed.
After washing out.
The end result was new bearing kit, and ring & pinion. The ARB was stripped & cleaned and was used again. A lot of money for the sake of an oil change!