Here are your parts includes a wiring diagram.
Replacement parts for pyet344aym models | AppliancePartsPros.com

When you replaced the thermal fuse did you also replace the high limit thermostat?
See item 5 in section 4.

The hi-limit should have regulated the temperature so that the fuse did not blow.
The only proviso here is that if you have a grounded element re: the element is broken or is sagging and touching the heater case. It can then run without regulation from any of the thermostats.

Check the heater coil for grounding. Unplug the unit, remove both wires from the heater and measure it, should be about 12 ohms. Then measure from each connector to the case, both should be open. Also visually inspect the unit, you may be able to see a burn mark on the inside of the case where the element has been heating up, then sagging and touching the case.
Check/clean your vent system
Check that the outside louvers open fully.
Check that the lint filter is not clogged up with fabric softener residue.
Check that the drum seals etc. from the heater to the blower are OK. The unit sucks air over the coils, through the drum and pushes it out the exhaust. The cycling (operating) thermostat is on the blower so if it sucks in too much room air past a seal it makes the dryer run hot.
Check that the blower wheel is clean and that it is firmly attached to the motor shaft.

If all the above are OK I would replace the fuse, the hi-limit thermostat and the cycling thermostat.

Here is a good site with additional info
http://www.applianceaid.com/dryers.html