Are these jacks rated for tongue weight? I see them rated fr 1000lbs, 1500lbs ect. I have a 21" CC Striper on my trailer. The jack seems to be stripped or something as I can turn the handle but it does not jack up. . I guess I will be buying a new one but do n0t want one which is under rated for the weight as perhaps the current 0ne may be.Trailer has a Hurley jack on it now . Can it be serviced?