If the U.S. economy is a highway, and the crisis in the credit markets a multicar pileup, then domestic automakers certainly have been caught in the traffic jam. One of them might be involved in the crash, though, and appears to have broken an axle.

Perhaps emboldened by the recent recovery in shares of Ford (NYSE: F), investors have applauded the results from General Motors (NYSE: GM) for the first quarter. Apparently, analysts were anticipating something worse than a $3.3 billion loss. It's clear there's some serious damage.

Of the $3.3 billion loss, $2.9 billion can be attributed to special items and $1.45 billion can be chalked up to the company's remaining stake in GMAC. Though the quarterly release said the carrying value of GM's investment in GMAC has been reduced to estimated fair value, uncertainty in the mortgage markets begs the question of whether further writedowns will be required.

Similarly, GM took a $731 million charge related to uncertainty surrounding parts maker Delphi's emergence from bankruptcy. This is another "one-time item" that leaves me wondering whether it's the last time. The ongoing strike at American Axle (NYSE: AXL) cost the company $800 million and 100,000 vehicles in the first quarter, and Fools need to look down the road for impacts next quarter as well.

There were some glimmers of hope: International sales grew to offset an 11.3% reduction in domestic sales volume. Following solid sales growth abroad, 64% of sales revenue now comes from outside the U.S.

GM sees economic conditions improving in the second half of 2008, as lower interest rates and the federal government's rebates kick in. These assumptions include internal forecasts for industrywide U.S. sales of more than 15 million light vehicles in 2008. Fools familiar with my work know that I find projections for a second-half recovery to be overly optimistic.

Americans are known for their love affair with cars, and I know many Fools love to love their auto stocks. As I noted recently in the case of Honda (NYSE: HMC), though, some caution is advised.

Further Foolishness: