@BB1959 did you find the answer yet? My 4600's just arrived (well, they arrived a few days ago but the tax man gave me detention)
Edit: I just found the repair manual on usb drive Iād bought when I bought my paper copy of the owners manual; Iād misplaced the thumb drive and forgot about it until today. Anyway, that manual indicates 59 lb. Ft. (80 Nm) for both upper and lower bolts and nuts.