Outer Limits 4x4 Board

Will had my 1994 shorty for about maybe 3 weeks now and all is good but started to notice a noise coming from the gears, for example in 3rd and 4th gear it gives out a loud rubbing sound. went under it to check out if the gears had any oil in them or if it had enough, but when i checked the oil it was on max, but what i noticed is that in the oil there were small chunks of metal in them??!!!! Something is really wearing off there or what can it be??

cheers for teh help in advance,

Danny