The Portuguese star reveals that he barely spoke to some of the club's senior players during his time at Old Trafford.
The Real Madrid star had been asked whether his relationships with teammates Karim Benzema and Gareth Bale, rumoured to be fraying, had contributed to Madrid's relatively slow start to the season.
However, the 31-year-old was dismissive of the impact that off-field dynamics have on on-pitch success and revealed that during his successful time at United he did not have much discussion with some of his teammates.
He told reporters: "I don't need to go out for dinner with Benzema or Bale. What counts is what happens on the pitch.
"When I was at Manchester winning the Champions League, with some players like Giggs, [Rio] Ferdinand and Scholes our discussions were limited to 'good morning' and 'good night.' But when we were on the pitch together there was total understanding.
Ronaldo enjoyed a hugely successful spell at United after breaking into the first team following his arrival as a teenager from Sporting Lisbon in 2003.
He scored 91 goals in 154 games over the course of his final three seasons in England, winning three consecutive Premier league titles as well as the Champions League and the Ballon d'Or in 2008.
Following his move to Real Madrid, he has reached new heights with his 345 goals in 330 games being rewarded with two further Ballon d'Or victories.