Try your hydro in third gear, you should get 6-7 MPH, check this with a GPS or annother vehicle if possible, just to make sure the moniotor is accurate. if it is lower than that, make sure your engine RPM is up to par, use a didgital tach don't rely on the monitor. if the engine Rpm is set to max and the speed is still low, there are a few possiblities, but they are all part of the hydro, like one person here had said, you can adjust the cable to compensate but I wouldn't recommend that, as you will disable the neutral safety, you will be unable to obtain neutral in the saftey slot tha is. the first thing I would check is the hydro pressure releif setting, by putting a guage in the motor at the a and b ports for for ward and reverse, holding the brake at high RPM and moving the hydro full forward, you should get 7000 PSI. if it is low the multifunctiuon valves are shot, if it is normal the hydro needs to be rebuilt or the feedback linkage in the control valve is binding, keep in mind tha tif the linkage is binding neutral should be difficult to obtain. good luck.