Disconnected dryer from the laundry room. Used telescopic camera to get a visual on the severity of lint inside the vent. Used extension brush on a drill to clean and remove build up inside the vent. Made 3 passes with the brush and verified lint removal with camera each pass. Sealed gap in the vent pipe connection where it enters the roof. Reconnected the dryer vent and gas flex connections, checked for leaks with bubbles. Turned dryer on to check operation after plugging it back in. Everything is working at completion of service.