Before using your MTD riding mower every year, you should do some preventative maintenance on the mower. With the gear shifting, backing up, going up hills and standard wear you put on the wheels and transmission of your MTD riding mower, you should definitely lube the rear end of your mower to prevent the axle and gears from overheating from friction and ultimately breaking.
Put the grease gun nozzle on the center of each rear tire grease zerk (located on the outside of the tires). Pump the grease gun handle until grease begins to squirt out around the rear axle of the MTD rider. Do this on both front tires, too.
Lay down behind the rear of the MTD rider mower.
Locate the frisbee shaped transfer gear case on the rear axle of the MTD riding mower. There will be a square bolt on the bottom and top of the gear case. Unscrew the bottom bolt with the crescent wrench. Position the oil drain pan under the case to catch the old oil. This is thick gear oil so it may take a while.
Screw the drain plug back in tightly. Unscrew the bolt from the top of the gear case. Put the funnel in the hole and fill the case to within a 1/4 inch form the top. Remove the funnel and screw the top plug back in.