Technically you could reuse your 18 tooth gear on the Lippert Components 2.5 x 2.5 Heavy Duty RV Slide-Out Gear Pack # LC123356, but if you're replacing the gear pack the gears themselves should probably also be changed. You can use the Replacement 18-Tooth Gear for Lippert RV Slide Out # LC122739 to swap the 15 tooth gears out for some 18's. view full answer...