set screw on the 2 speed clutch counter clockwise shifts at lower rpm, clockwise shifts at higher rpm. do 90 degree's at a time and re-run the car and see, i have had no luck with the redcat's shifting, its either way too soon, not at all or stay stuck in 2nd gear. i put a new 2 speed clutch in too, very sporatic. My other nitro's with 2 speeds works great, think its a design flaw with the redcats.