If you have not done so already, you need to open up the dryer and clean out any debris that is internal in the venting from the lint screen to the exhaust.

If this checks out, make sure the heating element is not grounded, and then try replacing the cycling thermostat. Here is the part

Part number: AP3131939

Look, your dryer has four thermal devices, a thermal fuse, two limit thermostats which are really thermal fuses and a cycling thermostat. The parts in the kit are limit thermostats that go on the heating element housing. the part I referenced for you is the cycling thermostat.

If you replaced two thermostats on the heater housing element, you did not replace the cycling thermostat which is on the blower housing. If you put the high limit thermostat in place of the cycling thermostat take it off and put it in the right place.

Also, your problem can be the blower is not functioning correctly or as we said, there is an air obstruction in the vent inside the dryer. You did not say if you checked this out, so if not, go there first. If all is clear replace the cycling thermostat and make certain you have the limit thermostats in the right place.