NEW YORK (TheStreet) -- Shares of Joy Global (JOY) are down over 6% Thursday following its disappointing earnings results, and that has TheStreet's Jim Cramer worried. The company missed on revenue and earnings per share estimates, and also reduced its full-year guidance. 

Joy Global makes machinery that is used to mine coal, Cramer, co-manager of the Action Alerts PLUS portfolio, pointed out during CNBC's "Stop Trading" segment. He noted that Joy Global's problems throw a light on Caterpillar (CAT) - Get Report , which bought mining equipment manufacturer Bucyrus at the top of the coal mining cycle. 

Caterpillar CAT and Joy Global JOY data by YCharts

It doesn't help that Caterpillar has seen orders decline and is seeing the rising U.S. dollar act as a headwind, Cramer added. 

Next quarter is likely to be disappointing, Cramer said, and he cautioned investors on the stock. "I don't know what to say about CAT," he concluded. CAT shares are down about 1% at close to $81. Its 52-week lows is $78.81. 

At the time of publication, Cramer's Action Alerts PLUS had no position in companies mentioned.