The U.S. full-size pickup market is incredibly lucrative for automakers, producing as much as $10,000 in profit per vehicle sold. Recently, General Motors (GM -0.05%) has been a step behind segment-leader Ford (F 0.17%) in this market. Combined sales of the Chevy Silverado and GMC Sierra were approximately 575,000 last year, while Ford sold 645,000 of its F-Series trucks.

GM revamped its Silverado and Sierra full-size pickups for the 2014 model year with the goal of boosting its share of the full-size pickup segment. The new GM trucks will feature better fuel efficiency than the outgoing models, and GM is also offering more premium options in an attempt to raise its average transaction prices.

The 2014 Chevy Silverado (courtesy of General Motors)

These new 2014 pickups began hitting dealer lots recently, and interest in the new trucks -- combined with a rebounding housing market -- has helped GM post strong growth in full-size pickup sales recently. However, Ford has still managed to stay a step ahead in terms of sales volumes. With a redesigned F-150 hitting the market next year, GM doesn't have much time to make its move if it wants to take the market share crown from Ford.

Full-size pickup sales soar
GM dealers sold nearly 60,000 Silverado and Sierra pickups in June, producing a second straight strong result after selling more than 59,000 in May. According to GM executives, roughly 90% of last month's truck sales were 2013 models, but 2014 models are starting to flow steadily onto dealer lots. Despite the prevalence of 2013 inventory in dealer stocks, incentive spending has been moderate in the face of a strong demand environment.

As strong as GM's results have been in the past two months, Ford has managed to keep its lead in the full-size pickup market. Last month, Ford dealers nationwide sold more than 68,000 F-Series trucks, marking the highest June sales since 2005. Ford posted even more impressive pickup sales numbers in May, as customers purchased 71,604 F-Series trucks. That marked the first time monthly F-Series sales eclipsed the 70,000 mark since 2007.

Is Ford pulling away?
After GM's pickups outsold Ford's F-Series trucks through the first two months of the year, Ford has come roaring back in the last four months. In the second quarter, F-Series trucks outsold GM's full-size pickups by roughly 15%. Through the end of June, Ford maintained an 11% lead over GM in full-size pickup sales for the year, nearly as good as last year's 12% differential.

If you're a GM shareholder, there's no need to panic -- yet. The 2014 Silverados and Sierras have been turning at a very high rate, spending on average just 10 days on dealer lots before selling. This indicates that demand for the 2014 trucks outstrips supply by a wide margin. As GM delivers more 2014 models to dealers, the company may have an opportunity to regain some share from Ford.

That said, Ford has achieved a ton of momentum with its relatively dated F-Series trucks, just when it was supposed to be GM's time to shine. With Ford's next-generation trucks expected to offer significant fuel-economy improvements over today's F-Series pickups, GM needs to seize the day if it hopes to challenge Ford's dominance of this segment.

Foolish bottom line
Pretty much anyone selling a full-size pickup in the U.S. has posted nice sales gains in 2013, due to resurgent demand. GM has been no exception, and the company sold more than 59,000 full-size pickups in both May and June. However, Ford has turned in even more impressive performances, averaging nearly 70,000 pickup sales in the last two months.

Last month, I pointed out that the lingering distaste for GM among many Americans could hurt its efforts to gain market share in the pickup segment. It's still early, but if GM doesn't start to reap the benefits of its new truck architecture soon, it could signal that the next-generation pickup market will tilt even more heavily toward Ford.