From Longman Dictionary of Contemporary Englishmove/get into top gearmove/get into top gearBUSY/HAVE A LOT TO DOto begin to work with as much effort as possible The party’s election campaign is now moving into top gear. → top gear
Examples from the Corpus
move/get into top gear• Accelerate smartly so that you can get into top gear as quickly as possible.• It was ready to move into top gear at very short notice.• Meanwhile Pistol Packer was getting into top gear on the stands side, and Caro and Arlequino were not done with. 