General Motors’ U.S. sales rose 10.4% in March on a daily selling basis, as new products such as the Cadillac ATS helped provide momentum to the auto maker’s four brands.

GM delivered 245,950 cars, trucks and cross/utility vehicles in the month over 27 selling days, compared with 231,052 over 28 days in like-2012, according to WardsAuto data.

The auto maker says it was its best March result in the past five years, with each division except for Chevrolet posting double-digit gains.

As other auto makers continue to report their results, it appears GM’s sales will come in slightly ahead of an industry trying to beat strong year-ago numbers. The Detroit Three collectively saw its best sales month since March 2008, according to WardsAuto data.

Cadillac and Buick witnessed the greatest momentum in the month for GM, as sales at the premium brands soared 55.0% and 42.5%, respectively. GMC rose 15.8% and Chevrolet notched a 4.2% increase.

“Cadillac and Buick were standouts in March,” Kurt McNeil, GM’s chief sales analyst, says in a conference call today with journalists and Wall Street analysts. He cites fresh product such as the all-new Cadillac ATS compact sports sedan and the redesigned Buick Enclave large CUV.

The ATS posted its best month since launching last summer on deliveries of 3,587 units, while the Enclave saw a 60.9% surge to 5,676 on the strength of major design changes and technology upgrades at the end of 2012.

Through the first three months, Enclave sales were up 44.4% to 15,812 units, with 40% of buyers returning to the CUV.

Don Butler, vice president-Cadillac marketing in the U.S., says the performance of the ATS was no 1-month fluke for the brand’s most important new product in more than a decade.

He expects the trend to continue, citing major improvements in consumers’ opinion of Cadillac with the addition of the ATS and how the sedan is driving brand sales to new highs in historically weak states such as California.

Roughly 70% of ATS buyers are coming from competitors such as BMW, Mercedes-Benz and Lexus, he adds.

“It’s compelling product,” Butler tells WardsAuto. “(Consumers) get behind the wheel and they love it and they talk about it. We’ve got tons of anecdotal stories of people being surprised that Cadillac has a vehicle like (the ATS), and that’s why we expect the momentum to grow.”

Butler reports 50% of buyers are choosing the 2.0L turbocharged 4-cyl. engine, which arrived late in the ATS launch. The naturally aspirated 2.5L 4-cyl. engine and range-topping 3.6L V-6 share the remaining sales evenly. Models leave dealer lots well-contented, he says. “We have the right mix.”

However, Cadillac sold only half as many vehicles last month than BMW delivered, while Mercedes-Benz moved nearly 13,500 more units than the GM brand.

Buick also gained momentum in the month from the Encore small CUV and Verano compact premium sedan, a pair of all-new vehicles for GM. The Encore accounted for 3,003 deliveries, while Verano surged 48.0% to 3,564.

GMC leaned on the redesigned Acadia large CUV, which saw sales spike 83.7% to 10,006 units in March. Sierra large pickup deliveries grew a tepid 3.5% to 13,817, while the Terrain 5-passenger CUV rose 3.6% to 8,454.

Sales of the Chevrolet Silverado large pickups bumped 12.4% higher to 39,561 units ahead of a redesigned-for-’14 model coming to dealers in about a month. The redesign includes three all-new engine choices GM claims will lead the segment in fuel efficiency and capability.

McNeil predicts an “orderly” sell-down of the current-generation Silverado and Sierra trucks, with GM staying away from deep discounts to clear lots for the new models. The two generations likely will sell alongside one another for much of the year.

“We’ve been working on this (sell-down) over 17 months of planning,” he says of the changeover, which entails keeping inventories at healthy levels while shutting down assembly plants to retool for the new trucks.

“We’re very comfortable where we are,” McNeil says. “We’ve been disciplined from an incentive standpoint, but having said that we’ll respond competitively. Our competitors are not sitting still.”

GM says its large pickup inventories totaled 239,718 units at the close of March for a 117 days’ supply, compared with 234,695 and 97 days’ in February. GM’s total vehicle inventory stood at 743,786 cars, trucks and CUVs for an 82 days’ supply.

McNeil says outside of rising taxes and lower government spending, the economy appears to be in good shape. Improved housing starts, jobs and consumer-credit sectors all are contributing to continued slow-but-steady economic growth, with the monthly seasonally adjusted sales rate remaining above 15 million vehicles as the year progresses.

jamend@wardsauto.com