Out of the 11 models represented on this month's list, only two had up months, with the majority of truck models showing a decline for June 2014. The two gainers for June were Ram, which posted a healthy 12 percent year-over-year gain, and the Chevrolet Silverado, which posted a modest 0.6 percent gain. The Ford F-Series, although still comfortably in First Place in overall volume, saw an 11 percent year-over-year June decline.

Across the board, the import-brand models were down, with the Nissan Frontier having the most modest decline at 5.7 percent. Somewhat surprisingly, the Chevrolet Colorado and GMC Canyon got a few "zombie" sales after flatlining last month.

1) Ford F-Series - 60,560, Down 11 Percent
The F-Series has led the sales charts consistently over the last three decades, but that's not to say Ford's trucks don't sometimes have an off month. The F-Series has typically outsold the Chevrolet Silverado and GMC Sierra combined, and that's still the case—although not by the usual margin. Maybe some buyers are holding out for the high-tech 2015 model.

2) Chevrolet Silverado - 43,519, Up 0.6 Percent
Sales of the Chevrolet Silverado have not been quite as meteoric as that of Ram, but they've been consistent. Compared to Ford's double-digit drop-off for June, the Silverado was up a smidgen for the month, and more than 10,000 units ahead of Ram, after a humbling Third Place finish in March.

3) Ram 1500/2500/3500 – 33,149, Up 12 Percent
Ram truck sales continue a torrid pace in June, being the only double-digit gainer for the month. The addition of the EcoDiesel and offering of the eight-speed automatic across the 1500 lineup is likely helping popularity.

4) GMC Sierra - 15,406, Down 7.0 Percent
The GMC Sierra saw a slight decline in June, down 7.0 percent. However, GMC has an unusually high sales mix of premium-trim models, which help the bottom line.

5) Toyota Tacoma – 12,173, Down 13.2 Percent
The current midsize sales leader saw a double-digit decline for June but still outsold the Nissan Frontier by more than a two-to-one margin. Expect things to get interesting once the 2015 Chevrolet Colorado and GMC Canyon hit the scene.

6) Toyota Tundra – 8.977, Down 8.0 Percent
The Tundra is still nowhere close to threatening the domestic sales hegemony but has a much stronger following than the current Nissan Titan, which is going on more than a decade without a significant redesign.

7) Nissan Frontier – 5,722, Down 5.7 Percent
The Frontier, which has enjoyed some strong months in 2014, took a bit of a downturn for June. Although Nissan has gone on record saying the Titan is the brand's top truck priority, the unveiling of a new global Navara model suggests a new Frontier may not be too far behind its big brother.

8) Honda Ridgeline – 1,309, Down 16.7 Percent
In its final model year, the Honda Ridgeline continues to have a small but devoted following of fans that appreciate its car-like handling and innovative packaging. The Ridgeline will be taking a sabbatical in 2015, to reappear in 2016 as a 2017 model.

9) Nissan Titan – 976, Down 24.9 Percent
The current Titan soldiers on until the all-new model comes, which is expected to be soon. Value-minded shoppers can probably find Titans for a steal, with generous incentives and dealers eager to move the slow-selling model off their lot.

10) Chevrolet Colorado – 51, Down 67.1 Percent
After zero sales last month, the Colorado shakes the richter scale a tad with 51 sales for June. Most likely a few fleet sales.

11) GMC Canyon – 3, Down 95.3 Percent
GMC sold three Canyons for June, keeping it off flatliner list for the month.