My information comes from two separate sources about the different cuts of the gears. Lead tech from Motive as well as the companies QC man. The other source of info I have about the cut of the gears is the Service manual that GM sends out to their dealerships which specifically states how the gears were cut different due to new CNC machines starting in 1998.

 

While at the Richmond booth at SEMA '04, I spoke with the National sales manager for Richmond gear. After he hit me with his sales pitch on their product, I informed him that the Richmond 4.10s in my Firebird whine quite a bit. He said the were not installed correctly and that I would have more serious problems in the near future if I didn't do anything. I then told him that the gears have been in the car for over 5 years with plenty of track abuse including several 1.8 60' times. He then offered to replace the gears free of charge, I declined his offer and told him that I wasn't gonna waste any more time on the stock 10 bolt. He seemed pretty insulted at that point and the other big wig there even chimed in about my "attitude". I just walked off.