Mark,the front main is different.The CL77 bearings didn't have a brown dot,mabe that's on GM400 shells..My 77's were marked on the back"A" (on 1 pair),"B" (on other 4),,I measured them and found a slight difference at the ends of "A" bearings.The Corsa tech guide describes why it was done-Tom --------------------------------- Do you Yahoo!? Check out the new Yahoo! Front Page. www.yahoo.com