I have a whirlpool dryer that will run for 30 to 40 minutes before shutting off. I have cleaned the lint filter and made sure I have air flow in the vent. If I let it cool off it will run for another 5 to 15 minutes before shutting off again. Any ideas about what else may be the problem? I also took the back off of the dryer and vacuumed around everything to make sure it was clean. As long as it is a fresh load out of the washer it will run longer but after they are only slightly damp does it start cutting off. I tried drying very small loads and that didn't help at all.

It could be the motor going out on the internal overload. Check to see if lint is all over the motor and blow out of winding area. This can cause them to get to hot and shut off.