One thing I dislike about my hydro is the reverse speed. All hydros make some noise. If your pump is making a loud annoying whine sound when the hydro is engaged it could be cavitating due to air or a restriction. This will rob the tractor of power and speed and may eventually damage the transmission. Consult your manual to see if the user can easily purge air from the hydrostatic transmission. If my memory serves me correctly, my MOWER manual indicates that air can be purged by placing mower on a level a surface engage brake, shut off engine, block tires to prevent rolling, engage the hydro release/transport/ bypass lever, start engine, release brake, operate directional lever forward and reverse multiple times, engage brake, stop engine, disengage the hydro release/transport/ bypass lever, and use as normal. This process has speeded up and quieted my reverse direction. I hope this helps.