The lint filter was torn in a couple of places. This let lint go into the dryer vent pipe over a period of years. I ordered a new lint filter and replaced it. I also pulled out the plastic piece the filter sits against and cleaned out behind it. The vent went to the roof. I pulled off the rain shield and found that the vent pipe was almost completely packed with lint. I pulled out all I could reach and nailed a 2x2 inch and 1x2 inch together and used it to scrape out the vent pipe. I placed a flashlight in the bottom and checked to see it was clean. I replaced the rain shield and carefully reconnected the dryer to the vent. Now the dryer runs cool as it should.
I just installed the new part. There were no tools required. I bought an extra part I ordered the part on Monday, and it arrivefor the other side in case it breaks. d by FedEx the next day. I live in Southern California.