Troxel moved north to the University of Idaho in Moscow in early 1967, as an assistant coach in both football and track. In football, he served under three head coaches in seven seasons: Steve Musseau, Y C McNease, and Don Robbins. He was named the head coach for the Vandal track team in May 1970, but stepped down when he became the head coach of the football team in December 1973. Troxel had turned down the head football job in May 1970 and again in December 1973, but later accepted after persuasion from his players and concessions from the new athletic director, namely a fourth assistant coach. His annual salary for the first season in 1974 was $16,500, which was $1,500 less than his predecessor That season was the last played outdoors in Moscow, as the new Idaho Stadium was enclosed and became the Kibbie Dome in 1975.