DETROIT -- Fiat-Chrysler CEO Sergio Marchionne said the next-generation Jeep Wrangler must be lighter and have more powertrain options to improve fuel economy.

"We know we need to update the architecture. We need to take weight out," he said.

The next-generation Wrangler is up for approval in the next 10 weeks, he said.

The Wrangler is available with a 3.6-liter V-6 gasoline engine and six-speed automatic or manual transmission. Jeep executives have talked about adding a diesel variant as well as more fuel-efficient transmission options.

Wrangler purists fear that the off-roader might lose its solid front axle in favor of an independent front suspension, but Marchionne, 61, said the issue is that Chrysler can't build enough to meet demand. Wrangler's U.S. sales rose 10 percent in 2013 to 155,502.

"The problem we have with Wrangler is that we are at capacity," he said.

Marchionne said expanding Wrangler production to meet worldwide demand is "on the table now," but reiterated that the vehicle would be built only in Toledo, Ohio.

The Wrangler was just one future product Marchionne discussed with journalists. He also said: