Welcome to the Cart Tek Service Support Center. The video below will assist you in removing and replacing a damaged gearbox on your GRX1200R or GRX1250Li. You will need a Phillips head screwdriver, a 4mm Allan wrench, and two 10MM wrenches, socket or open end. If you need further assistance, please don't hesitate to call. 541-633-4308 Please keep in mind a few tips to prevent gear box failure in the future. Consider the all-around weight distribution of your golf bag. Ensure the bag is balanced evenly side-to-side, but more importantly front to rear. The front wheel must stay grounded during play. The only exception is on steep inclines over 25 degrees. If the front wheel does come off the ground, avoid steering the caddy with the remote as this can cause the gear box to fail. If your front wheel tends to lift off the ground on slight inclines, try adding weight to the front of the golf cart. One trick is to place two water bottles filled with sand - one on each side - into low pouches on your golf bag.