i bought this honda 2000 used and the first time i tried to check the fluid in front diff it was full of mud.i have flushed it out with all kinds of stuff to clean it out.now it is fairly clean ,but every once in awhile it still sounds like the gears are just grinding in there.does anyone have any suggestions as what i could do to get it sounding better. someone told me to try lower unit grease for an outboard engine,but i am a little scared because i don`t know what the effects are.thanks