Building hydraulic transmission- not CUT

mygoatboy · Dec 20, 2005

I have a Farmall H (1940-ish) that has a shot tranny, all the gears are messed up. It is my loader tractor and I was wondering if anyone has used a hydraulic motor to drive the differential bevel gear? Basically I would get a pump that would be the most the engine could handle and then plumb it into an adjustavle flow control valve. From then it would be plumbed into a double detent valve to control forward and reverse. I want to do this to make it easier for loader work. Anyone with experience with hydraulics, there opinion would be greatly appreciated.

uhmgawa · Dec 20, 2005

( I have a Farmall H (1940-ish) that has a shot tranny, all the gears are messed up. It is my loader tractor and I was wondering if anyone has used a hydraulic motor to drive the differential bevel gear?)

You can do this but without variable gear reduction you will be
left with a single speed/torque range. So you will need to find if
you can strike a balance between drive torque and maximum
travel speed.

Winchester · Dec 20, 2005

I don't think you'll have any PTO if you change it over...

mygoatboy · Dec 20, 2005

Well as far as speed and torque... Can I get a variable displacement pump and/or motor? As far as a PTO, it is unneeded because this tractor never sees field work and there is a hydraulic winch permantly mounted that blocks it... Thank You

drmiller100 · Dec 20, 2005

variable speed hydraulic is called "hydrostatic." bring money, and do your research on gallons per minute vs RPM of the engine and the wheels.
a good site to find some inexpensive stuff is:
http://www.surpluscenter.com/

RonR · Dec 20, 2005

I'd think you'd have to build some pretty exotic mounting hardware to get it to fit where the transmission once stood. You'd need to have space for a large oil reservoir and a cooler. Moving a tractor, that oil will get HOT. And finding the right sized pump/motor combination to get you the right speed/torque range might be a challenge.

Doable, probably. Practical, don't know.

I'd probably try to find new gears and rebuild the transmission, but that's only me.

I went to a hydraulics seminar once where the sponsor had built a variable speed, 110volt, hydraulic pump/motor PENCIL SHARPENER! Doable, yes; gee whiz factor, you bet. Practical, nah.

Ron

Taylortractornut · Dec 21, 2005

Ive seen this done before but its more practical to use a transmission with it to for gear ranges. I think alot of HST tractors are like this. I know JD110 TLB's have them. THe tractor I saw had a loader and had been converted to hydrostatic, I surplus or used HST pump can bring around 750. THe best bet for the tractor is to get a Used tranny from a salvage yard I can set you up with a few good yards I deal with.

uhmgawa · Dec 21, 2005

( Well as far as speed and torque... Can I get a variable displacement pump and/or motor?)

This may well buy an extension of the operating range
but commercial designs still seem to require mechanical
gearing to achieve the desired range -- even in the case
of skid steers.

One possible quick and dirty way to circumvent mechanical
gearing would be to use two pumps. One sized for low-end
torque and the other for traveling speed. You'll need to work
through the details of how to allow the unused pump to
idle when the other is functional.

Have you given any thought to scrounging an auto manual
transmission to use between hydraulic motor and differential?

dfkrug · Dec 22, 2005

What about getting a a salvaged automotive AUTO
transmission? It seems to me that old Fergy loaders had
torque converters and multi range manual shifting trannies.
A working GM Turbo 350 or Turbo 400 might do it....

I made the "shift" to HST and I will never go back....

Renze · Dec 22, 2005

Yes i have had the idea of using the trans and engine of an old Mercedes Diesel car of my brother, as loader base... That 2.4 liter engine should do it and the transmission can also stand uo to a 3 liter petrol engine, so it should be able to take the torque in the heavy duty operation loaders require.

Anyways if you see yourself going into this, i would just start from scratch, throw away the tractor and keep both axles and the engine, and build the loader to the tractor rear end, and turn the new operators platform 180° to face the tractor (former) rear axle... that gives you much better vison of work, and 10 times better traction because when there is weight on the loader, there is also more weight on the driven axle.