hi,sorry if this seems a bit of a thick question, after competing a land rover 90 for years, i noticed there were no jeeps in the type of competition i do so i sold the 90 and decided to compete a 94 yj. . . i have just bought a d44 for the front of my yj, there is a large metal cover in the centre of the hub, at first glance i thought they where manual hubs, but they arent. .sorry if this seems bit vague but the original d30 on my yj hasn't got this and i am just wondering what they are and whether i should overhall before putting the axle on my jeep. . thanks jay