In May 1971, McKechnie was traded to the California Golden Seals and received a lot of ice time over his three years with the team, scoring 23 goals and 52 points in the 1973–74 season. In June 1974, he was involved in a three-way trade using the intra-league draft where he was claimed by the New York Rangers and immediately sent to the Boston Bruins for Derek Sanderson. He struggled with the Bruins and was dealt mid-season to the Detroit Red Wings. The next year in Detroit, he put up what would be his NHL career-high numbers, with 26 goals and 82 points, leading the team in scoring. McKechnie followed that a 25-goal season in 1976–77. After the season, he played for Team Canada in the 1977 World Ice Hockey Championships.