With the Moser rear cover removed, the 3:73:1 gears and Wavetrac limited slip are easy to spot. The three-series Wavetrac is fitted with 931- alloy side gears machined for much stronger 35-spline axles. Typical stock GM 12-bolts came with thinner, 30-spline axles. The Wavetrac case is also much more robust and made of billet steel. The Wavetrac does require special extra-cost carrier bearings.