Hydraulic/Hydrostatic questions

Following to a question that I asked earlier here.
Have old Dozer, Windolph Model F made in Portland Oregon in 50's.
Originally had Wisconsin Model TF engine, 14hp at 2800 RPM 32 ft/ibs torque.
Had Crosley 3 speed transmission. 1st 3.29-1, 2nd 1.72-1 and 3rd 1-1.
So in 1st gear the input shaft to the rear differential is turning at a Max of about 900 RPM.
So in the dozer version that I have the Wisconsin engine and Crosley transmission have been removed
and replaced with a Duetz Diesel that puts out 34 HP at around 2800 RPM and 64ft/ibs of torque.
On the back of the Duetz is a hydraulic pump, Plessey Turolla 200. Do not know the pressure or flow of this pump.
The hydraulic motor on the input shaft of the differential is a Eaton 103-103 that according to specs will max out at 985 RPM.
So that means that this dozer in base case scenario is running around in low gear all of the time.
So my hope is to find a used Hydrostatic motor off of a old Swather or combine or something that I could install in place of the hydraulic motor that is there now. I only have about 12 inches of room between the back of the hydraulic pump and the input of the differential shaft.
Any suggestions on where to find a hydrostatic motor, I think they call them variable vane motors, that could work in this application?
Thoughts
Marvin Johnson

"Eaton 103-103 that according to specs will max out at 985 RPM"

The speed of that motor is determined by the GPM's of oil fed to it, NOT some arbitrary "985 RPM limit".


NOT sure what you wanna do, but if you want it to go faster, replace the hydraulic motor with a smaller displacement version.

Hoping to find a hydrostatic hydraulic motor that vary the speed and torque to somewhat match the performance of the original three speed transmission.
Similar to the hydrostatic transmission on a riding mower

From what I can gather by googling the pump name this must be a gear-type, fixed displacement pump, correct? If so you must have a flow and directional control valve to do the variable speed drive and reversing functions? (If so this would be somewhat similar to a Case or Ingersol garden tractor.) Unfortunately I wasn't able to find out based solely on your descriptions the displacement of either the pump or motor and this is the most important piece of information required when sizing hydro drives. The Eaton 103- series motors does not show a -103 size; following their convention a -103 would be 103 cm^3/rev. They show -97 and -120 sizes but their max speeds are in the 400-600 range so I'm not sure what you have. Without knowing the pump and motor displacements and their respective pressure limits there is no way to tell what the complete effect will be of swapping components.