Technician arrived to perform a yearly friends and family club furnace maintenance on three 1999 systems technician inspected the heat exchanger adjusted the gas pressure monitored blowers amps and temperature. Differentials technician found the transformer on the main system. Humming really loud and getting really hot would recommend replacing it to prevent the System from breaking down technician also found on the living room unit heat exchanger some very concerning spots did not find any rust holes or brakes, but explain to the customer the concerns will have Tim reach out to give him repair versus replacement options so that way he can look over and make a decision