Are either or both of these following products equivalent to the above? : AC Delco Axle Lubricant SAE 80W-90 GL-5 10405-1 89021669 and GM Vehicle.Care Axle Lubricant SAE 80W-90 APL GL-5 89021669. If so, are these two products the same as one another? I own a 1987 Morgan Plus 8 with an unobtanium...