His daughter announced his death in a Facebook post.
Pacheco met Ali, then known as Cassius Clay at Miami's 5th Street Gym in the early 1960s when the future heavyweight champion was training with legendary trainer Angelo Dundee.
Pacheco joined forces with Dundee as Ali rose to prominence in the 1960s and remained in his corner throughout most of his reign as the heavyweight champion.
Pacheco also played a key role in Ali's first fight that won him the heavyweight title in 1964 against Sonny Liston.
Ali's blood pressure rose at the weigh-in and Pacheco was asked to examine the fighter away from the atmosphere. Ali told Pacheco he was acting "crazy" to scare Liston but when Pacheco examined him, the reading was normal and Ali won the fight in six rounds.
Later on, Pacheco became concerned about the increasing blows absorbed by Ali. He voiced his concern following the 1975 "Thrilla in Manila" when Ali retained his title by beating Joe Frazier.
After Ali beat Earnie Shavers in 1977, Pacheco sent letters to Ali urging the champion to retire but received no response.
Ali's boxing career ended in 1981 and he soon began a 32-year fight with Parkinson's disease until his death at the age of 74 in June 2016. His career record was 56-5 with 37 wins by knockouts.
Pacheco's broadcasting career began shortly after Ali beat Shavers.
He was the analyst for CBS for Ali's fight against Leon Spinks and then went on to broadcast for NBC, Showtime and Spanish-language network Univision. Pacheco also won two Emmy awards, including one for a series on Ali's career.
Before entering boxing, Pacheco graduated University of Florida with a degree in pharmacy and received a medical degree from the University of Miami.
Besides helping Ali, Pacheco provided medical assistance to 12 world champions trained by Dundee.
