Let's get something out of the way before we dig into August's sales takeaways for Ford Motor Company (NYSE:F), General Motors (NYSE:GM), and Fiat Chrysler Automobiles (NYSE:FCAU): The auto industry's meager 0.6% decline in new-vehicle sales last month has nothing to do with the recent market pullback, or consumer pessimism, or concerns about China and/or the global economy -- just in case that wasn't already clear.

The auto industry was up against very strong comparisons from last August, aided by the fact that a very strong selling holiday, Labor Day weekend, was counted in August last year, but will be counted in September this year. On top of that, there were 26 selling days in August 2015 compared to the prior year's 27. Basically, the deck was stacked against the new-vehicle sales in August in terms of year-over-year comparisons, but overall, the seasonally adjusted annual selling rate, or SAAR, for light vehicles soared to 17.81 million in August, which was the highest pace since July 2005. 

Despite fewer selling days and a missing holiday weighing down last month's year-over-year sales comparisons, there are some very favorable figures coming from Detroit automakers. Let's start from the top, in terms of overall sales volume.

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Chevrolet's 2015 Silverado is selling well at retail. Image Source: General Motors.

General Motors -- 270,480 units sold -- 0.7% decline year over year
Looking at all of the brands under GM's umbrella, GMC and Buick managed to post respective gains of 3.5% and 0.6% in August compared to last year. On the flip side, Chevrolet and Cadillac posted respective declines of 1.5% and 5.5%. All in all, that adds up to a decline of 0.7% for GM in August compared to last year.

While General Motors' overall sales declined slightly last month, its retail sales checked in at a healthy level. GM's retail deliveries moved 6% higher compared to last year's August, which, again, included Labor Day sales, and fleet sales checked in 24% lower. As GM's retail sales moved higher, and fleet sales moved lower -- especially rental sales, which moved 28% lower -- it should reinforce GM's solid EBIT-adjusted margins in North America.

"GM's retail sales increase far outpaced the industry in August, and we have grown our retail share for five months in a row compared to last year," said Kurt McNeil, GM's U.S. vice president of sales operations, in a press release. "We will continue this momentum with the redesigned Chevrolet Cruze and Malibu, the launch of diesel engines for our midsize pickups, a dramatic restyling of the Chevrolet Silverado and the aggressive rollout of Apple CarPlay and Android Auto."

A real bright spot in GM's August sales data was from its pickup trucks. Detroit's largest automaker has recorded an increase in Chevrolet-brand truck sales for 16 consecutive months, and August checked in with a 26% increase in pickup deliveries. The Silverado, GM's bread-and-butter full-size truck, posted a 12% increase in deliveries, and a 20% increase in retail sales -- its best August retail sales performance since 2008.

Furthermore, GM's average transaction prices, or ATPs, were $34,000 in August, which was an increase of $660 year over year. GM's Chevy Silverado and GMC Sierra fueled those ATP gains, and the two sister trucks' combined ATPs were up roughly $1,400 year over year in August.

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Ford's 2016 Explorer. Image source: Ford Motor Company.

Ford Motor Company -- 234,237 units sold -- 5.4% increase year over year
Ford investors have patiently waited for sales to improve in 2015 after a year when Ford released more new and significantly refreshed vehicles than it had in any other year in company history. Finally, August proved to be a breakout month for Ford.

Sales of newer vehicles really fueled Ford's sales last month. Ford's F-Series posted its best August sales result since 2006, with sales topping 71,000 units. Sales of the F-Series increased 5% overall from a year ago, with retail sales jumping 15%. Better yet, Ford noted that 63% of F-150 retail sales in August were vehicles equipped with the EcoBoost engine, which was an 86% increase compared to last year. The increase in F-150 sales with EcoBoost is good news for investors because the engine option sells at a premium to Ford's V6 option.

As SUV sales continue to thrive in America, Ford's newest SUVs posted significant gains. The Edge and Explorer posted respective sales gains of 36% and 22% in August compared to last year, and were staying on dealership lots for only 20 days and 16 days each -- a far cry from the industry average of roughly 60 days. Ford's total utility/SUV segment sales improved 12% compared to last August, and marked the best August performance for the lineup since 2003.

Ford's iconic Mustang wasn't to be left out of the sales party last month. The Stang posted another excellent month, with a 70% sales gain compared to last year's August, which was its best August performance since 2007.

Fiat Chrysler Automobiles -- 201,672 units sold -- 1.7% increase year over year
Looking at FCA's collection of brands, Dodge and Chrysler disappointed in August, with respective sales declines of 15% and 14% compared to last year, and Fiat barely managed a 1% gain.

It shouldn't come as any surprise that Jeep again led the FCA brands in terms of year-over-year sales gains, with an 18% increase, compared to last year's August. It should be noted, however, that 8,156 units of Jeep's roughly 12,000-unit gain last month compared to last year's August was due to the Renegade, which is being compared to zero units sold during last August.

As SUV sales continue to drive higher in the U.S. market, Jeep has posted huge annual sales gains.

Jeep
*2015 estimated using sales pace through August. Chart by author. Data source: GoodCarBadCar.net.

"In spite of a tough 2014 comparison and extreme stock market volatility, our dealer's competitive spirit kicked in and propelled us to our 65th-consecutive month of year-over-year sales increases," said Reid Bigland, head of U.S. Sales, in a press release. "Our Jeep brand turned in a double-digit increase while eight individual models, including four Jeep brand vehicles, set sales records. FCA US topped the 200,000-unit threshold in August for the second time this year."

Another brand posting healthy growth and keeping the lights on at FCA headquarters was Ram. While the Ram pickup lagged slightly behind Ford's F-Series, and quite a bit behind GM's Silverado, it managed to increase sales by 4% during a month that lacked the typical sales surge from Labor Day.

Ultimately, with gas prices remaining cheaper, and credit easily available to consumers, expect sales of highly profitable vehicles to remain robust -- and that's good news, regardless of which of these three automakers you're invested in.

Daniel Miller owns shares of Ford and General Motors. The Motley Fool recommends Ford and General Motors. 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.