Murray riding mowers use a mechanical assembly to shift gears. You can select multiple options for forward or reverse directional mowing. This assembly is made up of hardware and linkages that interact with the brake and drive systems. If you are trying to shift gears but your Murray riding mower is stuck in neutral, it's time to inspect these assemblies.
The shifter assembly on your Murray riding mower is separate from the clutch/brake and throttle assemblies. Although the shifter has a protective housing, it's possible that small objects or sticky liquids can enter the gear shift area and bind the mechanism, preventing you from selecting forward or reverse direction controls. Also inspect the linkage between the gear shift and the drive axle. Broken or obstructed linkage can prevent shifting.
Over time, your Murray riding mower's shift lever can come out of alignment and the neutral position on the lever won't match the neutral position in the gearbox. If this happens, you can adjust the shift lever by first stopping the engine and then disconnecting the adjuster nut from the shift bracket. Put the gear shifter in the "neutral" position and then push your mower forward until the gearbox is showing the neutral position as well. Replace the adjuster nut on the shift bracket while keeping the shifter and gearbox in neutral positions.
Brake and Clutch
Murray riding mowers require you to press the clutch/brake pedal before using the shift lever. You also have to move the throttle lever to slow. If there is interference with the brake/clutch pedal, your gear shifter may not come out of the neutral position. Inspect the linkage between the clutch/brake assembly and wheels, as well. Any damage or obstructions should be repaired immediately since this also causes a safety issue. The mower's operating instructions include directions on how to adjust the clutch, if needed.
Motion Drive Belt
Once you select a gear with the shift lever, the motion drive belt circulates around a pulley system to push the drive axle forward or in reverse. Belts can become worn and damaged over time due to rough riding or getting something lodged between the belt and pulley assemblies. Keep your Murray mower clean to prevent objects from interfering with the mechanics. Inspect the belts for slippage and wear prior to use. Also inspect the pulleys for damage. Keep all lubricants and grease off the belts to prevent slippage.