Ford Motor Co. said Thursday it ordered dealers to stop selling hundreds of its 2002 model Ranger pickup trucks because of a problem with the vehicles' rear axle.

"This is a stop sale, stop demonstrating and delivery," Ford spokesman Mike Vaughn said of the company's unusual order, which he said was issued to dealers on Monday.

He said the order affected 804 Rangers on dealer lots with manual transmissions and the new FX4 design package, which gives the vehicles a rugged, off-road look.

Another 374 of the pickups, which are already in customer hands, will be recalled by Ford, Vaughn said.

The problem with the trucks stems from a bad differential casting, he said, adding that they could be fixed only by replacing the entire rear axle assembly.

Nick Scheele, Ford's president and chief operating officer, has said improved quality is a critical goal of the turnaround plan the company unveiled on Jan. 11 after last year's multibillion-dollar loss at the world's second-largest automaker.

A tattered balance sheet, coupled with the Firestone tire fiasco, a rash of quality problems and poor new vehicle launches paved the way for the ouster last October of Ford's former chief executive, Jacques Nasser.