Dryer Stops Running

My dryer will only run for a a minute or two before it shuts off "dead" if I go and reset the breaker it will run again. I cleaned the exhaust vent and let it run empty for 30 mins on "time dry" it heats well appears to vent very well and it did not shut off. When I put in a load it only ran for about 5 mins before it shut down and required another breaker reset.

Any ideas appreciated.