[Richard]

Jim,

Take a look at the aluminum manifold block where the solenoid is located. I think you may find an adjustment screw for the low speed circuit. I think, but I'm not sure, that you could increase the fan speed by backing out that screw.

I also think, but don't have the data to prove it, that the reason that we are all over the board on the low fan speed is that it could have been set differently at the factory, or age and miles have altered the fan motor, hyd pump pressure, or orifice in the low speed circuit.