Big sales of F-150 pickups powered good results for Ford in September -- and big profits that may have come at GM's expense. Will those gains continue? Photo credit: Ford Motor Co.

Ford (NYSE:F) made solid gains in a tough U.S. market in September, thanks to strong sales of its F-Series pickups. Many of those sales came at the expense of old rival General Motors (NYSE:GM), as many buyers shied away from GM's all-new Chevrolet Silverado.

Was that a one-month fluke, or the start of a new trend? In this video, Motley Fool contributor John Rosevear looks at the latest analyst reports on the state of the U.S. auto market, and predicts how Ford and GM will fare when the latest sales numbers are released this Friday.

Fool contributor John Rosevear owns shares of Ford and General Motors. You can connect with him on Twitter at @jrosevearThe Motley Fool recommends Ford and General Motors. The Motley Fool owns shares of Ford. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.