Get Monzeamon and go to toy land.(Make sure you have a lot of MP med recovery's, and HP med recovery's, about 20 HP rec. and 10 MP rec. )Then make sure your digimon sleeps then save it. Then go to the little robot space ship for a little Tinmon to open the Toy land mansion door.Then go inside till you reach two box's. Piick the little one then beat Warumonzeamon. After you beat him it will say "Thunder Justice Learned". If it doesn't restart the game and do it all over again till you learn it.

Note: When Warumonzeamon gives you a gear don't give it back to Tinmon until you get 97 digimon in you city and beating Machinedramon.