By the end of 2007, GM expects to have its approximately 8,000 U.S. and Canadian dealers using its Retail Inventory Management (RIM) system, which relies on intelligence gleaned from nationwide parts sales to recommend parts-restocking policies at dealerships.

Today, GM parts distribution relies heavily on the judgment and practices of individual dealer parts managers, who typically wait until the end of the week to submit a batch of parts orders. This has meant that a large percentage of parts orders have arrived at GM distribution centers at the same time, driving up labor costs because workers earn overtime pay as they rush to fill orders.

"Our order variation from Monday through Friday was 21 percent -- Monday and Tuesday we're working overtime and toward the end of the week we're looking for volume," said Bryan L. Burkhardt, global director for retail inventory management at GM Service and Parts Operations.

A pilot program at a regional distribution center in Jacksonville, Fla., that involved 350 dealers earlier this year proved the technology for GM. Instead of a lopsided approach with weekly batch orders, the RIM system responded to actual daily demand -- and the daily order variance was cut to 2 percent at that center, said Burkhardt.

More important for GM is ending the customer dissatisfaction resulting from the automaker's legacy ordering system. GM was concerned that customers who were unhappy because they had to wait for parts would be more likely to buy their next car somewhere else, said Burkhardt.