"Right now, people are buying new cars rather than used cars," he said.

He predicted that all car sales are likely to slow as the November presidential election approaches.

"Consumer confidence may slow down a bit," he said.

Credit unions must take advantage of the growth in both new and used car purchases, Boutelle said.

Boutelle's organization — based in Ontario, Calif. – and others like it offer credit unions a variety of services that use technology to help speed up lending in several areas, including auto loans. For instance, such services allow credit unions to offer branded shopping services to members who are considering a vehicle purchase. And the credit union can follow up with the member who also may be shopping for a new home or credit card.

"Millennials expect that credit unions can respond as quickly as Amazon can," Marci Francisco, the company's vice president for automotive marketing and business development, added.

Francisco said Google recently did a study about "micro-moments" and the desire consumers have to make instant decisions about such things as purchases no matter where they are.

Now, the key is to be able to help prospective auto purchasers get to the point of purchase even before they visit a dealer.

Francisco said companies such as AutoTrader are recognizing how huge of a market credit union members can be for vehicle purchases.

"Credit unions are talking to their members about auto loans," she said, adding that as a result, "Inventory aggregators are looking at the credit union space."