dryer would keep running and never dry close. No heat.

Unplugged the dryer, Very important, there is voltage on on of the wires to the heater.
I first removed the 2 screws on the lower part of the front cover and rotated this out of the way, no need to disconnect any wires. removed 2 small screws that hold the heater assy. cover plate and the one screw in the front bottom of the heater assy. I then removed the one screw at the top back of the heater. this completely frees the heater assy.
I then removed the push on wire from the thermistor and the other wire from the lug and I transferred the thermistor to the new unit. Now it is time to reverse the process making sure the entire circumference of the heater assy goes into the hole in the back. This can be a little tricky if the new assy is out of round. Just work it in, it will fit. Very easy, only about 20 min from start to finish...