There's no question that automakers have been jumping over one another to get their fair share of new-vehicle sales in the growing Chinese automotive market. The surge in China's middle class has generated huge sales growth in new-car sales during the past five to 10 years, and the best could be yet to come.

Consider that some analysts expect new-vehicle sales in China to top 30 million annually by 2020, compared to just under 20 million units sold last year. That means that China is projected to generate nearly one-third of the entire planet's new-vehicle sales by 2020.

At first glance, this is good news for General Motors (NYSE:GM). In the first half of 2015, GM set a record and tallied up 1.72 million retail vehicles sold in China -- more than the 1.1 million retail units it sold here in America. However, let's take a look at GM's sales in the world's largest automotive market and see if there's actually trouble in paradise.

By the numbers
Digging into the details, GM and its joint ventures posted record retail sales of more than 246,000 units in China during June. Through the first half of 2015, GM's sales in China increased 4.4%, led by a rise in SUV sales, which surged more than 82% compared to the first half of 2014. Sales of multipurpose vehicles, or MPVs, also increased 31%, and sales of GM's luxury Cadillac lineup moved a healthy 14% clip higher, again compared to the first half of 2014.

In fact, there were quite a few bright spots for GM investors who are hoping that China will help drive revenues and profits higher in the years ahead. Buick had its best first half ever in China, with sales 4.3% higher compared to the first half of 2014. Cadillac also set its own first-half record in China, and sales of the Chevrolet Cruze -- Chevy's most popular model in China -- set the model's first-half record with nearly 125,000 units sold at retail. So, at first glance, everything looks great for GM, right?

While GM did set plenty of sales records, there still appears to be some trouble in paradise.

Pricing woes
If you follow the stock market, you've probably heard that China's economy is losing some steam and that its benchmark Shanghai Composite Index lost roughly 30% of its value in about three weeks' time. That wealth reduction appears to be causing a slowdown in demand for new vehicles. However, that economic slowdown is happening at the same time that Chinese automakers are grabbing market share from foreign automakers by flooding the market with more affordable SUV models. With increased competition and a slowing economy, it has forced foreign automakers to slash prices.

In fact, in May General Motors cut prices on 40 models sold in China in an unusually large fashion: GM's price reduction on the Chevrolet Captiva SUV was a staggering 20%. Volkswagen and its two joint ventures, which combine with GM to control 30% of China's passenger-vehicle market, slashed prices on its entire lineup by $800 to $1,600 per model.

"This is a permanent move downwards in pricing," James Chao, the Shanghai-based Asia-Pacific managing director at IHS Automotive, told Automotive News China. "There are few signs of the trend letting up."

One reason pricing is so important to foreign automakers selling vehicles in China is that they are forced into joint ventures with Chinese automakers. As you can see in the chart below, GM owns roughly 50% of the sales it generates with its joint ventures, making pricing and margins more important on each vehicle.

Image source: General Motors Behind the Charts presentation.

Ultimately, it will be important for GM investors to watch how new-vehicle sales in China progress throughout the back half of 2015. GM plans to launch the new Chevrolet Malibu and Baojun 560 SUV in China before the books are closed on 2015. Furthermore, the Buick Verano just launched in China last month, and GM plans to increase the production of the Buick Envision, though it hasn't revealed how large that increase will be.

Despite recent pricing concerns, if GM can continue to drive sales of its SUVs and Cadillac lineup higher along with the previously mentioned new launches adding to incremental sales, 2015 should still finish up as a great year for the automaker and its investors.