When Minato used KCM, a lot of people pointed out how when Minato got Kurama's chakra, he died and had no time to actually fight Kurama and get control over him. A lot of people cite this while talking about the current Kakashi fiasco. However, what if people were wrong? What if there was a time where Minato was able to talk to Kurama and gain control?
This time was when the Edo Hokages were rushing to the battlefield. While Minato was heading to where Naruto was, he entered the astral plain where a host talks to the Beast and talked to Kurama. Minato has shown he has a far more enduring personality than Naruto, so perhaps his approach managed to get that half of Kurama to listen to what he had to say. He explained what was happening, and when that half realized that Tobi succeeding would mean his end, he agreed to loan Minato control in order to help put him down. This is pretty much half of the reason as to why the half of Kurama in Naruto agreed to give him control. Kurama isn't stupid, so he listened to Minato's reasoning.
Now one could argue that there isn't enough time. Well, we've seen that time passing in the Tailed Beast astral plane isn't the same as time as passing in the real world. Naruto, Sasuke, Bee and Minato himself has had conversations in their head with Beasts and no time passed whatsoever in real life, or if it did, it was miniscule. It's possible that Minato's approach to Kurama and the circumstance allowed for Minato to gain control faster because Kurama agreed to give him chakra without a fight and tug of war.
Now you could also argue that Minato couldn't have gone to the Falls of Truth in Kumo. Well, Danzo said Yagura was a Perfect Jinchuriki and it's doubtful that he went to the Falls. This shows going to the Falls and doing Killer Bee's method isn't the only way to do things, so it doesn't make this scenario impossible.
TL;DR: Minato reasoned with Kurama while traveling to the battlefield, and Kurama agreed to grant him control to eliminate a common enemy.
This time was when the Edo Hokages were rushing to the battlefield. While Minato was heading to where Naruto was, he entered the astral plain where a host talks to the Beast and talked to Kurama. Minato has shown he has a far more enduring personality than Naruto, so perhaps his approach managed to get that half of Kurama to listen to what he had to say. He explained what was happening, and when that half realized that Tobi succeeding would mean his end, he agreed to loan Minato control in order to help put him down. This is pretty much half of the reason as to why the half of Kurama in Naruto agreed to give him control. Kurama isn't stupid, so he listened to Minato's reasoning.
Now one could argue that there isn't enough time. Well, we've seen that time passing in the Tailed Beast astral plane isn't the same as time as passing in the real world. Naruto, Sasuke, Bee and Minato himself has had conversations in their head with Beasts and no time passed whatsoever in real life, or if it did, it was miniscule. It's possible that Minato's approach to Kurama and the circumstance allowed for Minato to gain control faster because Kurama agreed to give him chakra without a fight and tug of war.
Now you could also argue that Minato couldn't have gone to the Falls of Truth in Kumo. Well, Danzo said Yagura was a Perfect Jinchuriki and it's doubtful that he went to the Falls. This shows going to the Falls and doing Killer Bee's method isn't the only way to do things, so it doesn't make this scenario impossible.
TL;DR: Minato reasoned with Kurama while traveling to the battlefield, and Kurama agreed to grant him control to eliminate a common enemy.
