I did have it serviced, blades, oil, ex... Not sure if these things were checked? I will check them out - Thank you. The clicking sounds like two gears that aren't making a good contact. But I will check out the items that you mentioned thank you.Before blaming the tranny check the drive belt, tensioner pulleys and tensioner arm. Old worn belt (more than 3 years), pulleys with worn bearings, tensioner are which does not move freely will cause these symptoms. When was the last time these parts were checked or replaced?