Mr. Stephenson held a prolific career in acting beginning in 1948, having partaken in radio, television, and film acting. Among his most notable voice acting roles was Fred's stern boss Mr. Slate on The Flintstones, and his voice was heard in the 1960s Dragnet TV series, on which he would announce the verdicts at the end of each episode.
To Transformers fans, he was best known as the voices of Alpha Trion, Thundercracker, Kup (seasons 3-4 only, not the movie) Windcharger, Huffer, Devcon, and several other smaller roles in the G1 cartoon.
Our prayers and blessings go out the family and loved ones of Mr. Stephenson. He will be missed.