According to Sri Yukteshwar-ji, Treta Yuga ended around 3100 BC. And according to the Vedas and other calculations, the Mahabharata happened at the end of Dwapara Yuga, exactly around 3137 BC. This brings me to the question whether the Mahabharata happened during Dwapara Yuga, or during Treta Yuga?
Yes, the Scriptures say that the Mahabharata occurred during the end of Dwapara Yuga, and that Krishna left his body right at the moment when Dwapara Yuga (the age of energy) turned into Kali Yuga (the dark age).
However, according to Sri Yukteswar’s calculation that moment when Dwapara Yuga turned into Kali Yuga was not in 3137 BC (which is the time when Treta Yuga turned into Dwapara Yuga), but in 700 BC.
In short: the Mahabharata happened during Dwapara Yuga, right at the end of it.
For detailed information about the Yugas you may study the fascinating book “The Yugas”: https://www.crystalclarity.com/shop/books/the-yugas/
All the best,