im taking the front diff apart and putting oil in it for the first time, i cleaned all the grease out and put 5k diff fluid in it and putting it back together and when i spin the diff its gritty and dosnt feel right and when i put it in the truck when i turn the wheels it feels like its grinding 1/4 way in the turn of the wheels. ive only done the front diff so far and its done right any of you guys have this problem or is it normal?