A predictive pitting model for gear design applications was recently developed by Blake and Cheng (1), (2). Life estimates were based on predicting the growth of surface-breaking cracks leading to pit formation. While trends predicted by the model reflected observed behavior, estimated lives were lower than expected. The crack growth model has been improved by modifying the original shear-driven, two-dimensional propagation model to reflect three-dimensional cracks driven by both shear and lubricant pressure effects. Resistance to crack growth due to friction between the crack faces has also been considered. These changes have led to a net increase in predicted lives, which better reflects observed pitting behavior.Presented at the 46th Annual Meeting in Montreal, Quebec, Canada April 29–May 2, 1991