NEW YORK ( TheStreet) -- Last week the auto industry reported that June auto sales came in at the fastest pace in six years. Between July 23 and Aug. 9 the 10 auto makers I profile today report their quarterly earnings. The key will be the revenue line and forward guidance to judge whether or not the sales gains can be sustained.On July 2 when I wrote, Sector Ratings Set Asset Allocations, I gave the autos-tires-trucks sector an 'avoid-source of funds' asset allocation rating. Today, following benchmark revisions to ValuEngine data, the autos-tires-trucks sector consists of 94 stocks with only two rated buy. The number of sell-rated stocks declined to 31 from 67 which justifies an asset allocation upgrade to underweight. This assessment still justifies profit-taking on strength in the sector. Seven of the autos I profile today are rated hold, while the other three are rated sell. Higher U.S. Treasury yields should have a negative effect on auto and truck sales as rates on auto loan rates rise. Auto loan default rates have been inching up recently, which could become a drag on auto sales in the second half of 2013. An interesting observation among these stocks is the different price patterns among the American auto companies compared with European and the Japanese stocks. Ford Motor ( F) set a multi-year high on Friday with General Motors ( GM) close behind. Some of the European based manufacturers peaked in the first half of 2013; others peaked in early June. Meanwhile the Japanese auto makers peaked with the major U.S. equity averages around May 22.