d4 hydraulic pump

I'm not sure how much horsepower that gear set can deliver safely. It is designed more for rpm turning a relativelty easy load (the generator). If you selected a hydraulic pump that delivered the gpm at the RPM the generator is turning, you might have good luck.

Also depends on what you will be running with the hydraulics. CAT designs of the time were high volume relatively low pressure arrangements with large diameter cylinders. A #44 control on a D4 for a dozer would typically be 25 GPM @ 1000 psi while turning 1400 rpm. Or about 15 hp maximum for short periods. PSI x GPM divided by 1714 = HP

As a comparison, the generator for a direct start 24 volt system might have been 18 amps. 24 x 18 divided by 743 is about 0.6 hp at 100% efficiency so maybe 1 hp load on the gear drive in actual operational efficiency.

It seems that the size of the gears would be plenty, they are only half the width of most manual trans gears that take 400 horse in a car and this would be a smooth almost constant load. Thanks for the info on computing horsepower required, that kind of info is what makes this forum great. The other reason I was thinking of this being possible is that the D4D my Cousin has is set up this way from the factory. If I can find a hydraulic pump that will deliver the correct flow/psi and has a through shaft I could even drive an alternator off the rear of the pump and keep all of it contained behind the engine side cover. Maybe I am dreaming and making it overly complicated but it seems this would be a good way to package/protect both systems. Anyone know how to determine the strength of the factory gear drive without breaking it?😊
Again all the input is great and I don't think the fabrication would be that hard to make it work.

I agree that the size of the gear suggests they are more than strong enough to drive a pump and alternator. I like your idea of running both back to back. Unless the gears are made from very soft material, I suggest they would easy handle 10-20hp given their sheer bulk

The other consideration would be the bearings - I'm not familiar with how to determine what hp/torque a given set of bearings could handle but I'm sure someone here does. Confirming that would put you in good shape I think, and then lastly what the lubrication capabilities are under that load. Not saying it's a problem but confirming it would remove any doubt.
I have a 3JD2 that I'll get around to putting an hydraulic pump on for rear-mounted implements - if I could have it in the engine bay rather than on the front of the radiator, I'd feel more comfortable given how many times I've bumped the front of vehicles over the years : )

Cheers,
Neil

Neil, I feel the same about the front mount. My D4 has a front mounted pump with a guard, but I still want to move it. I'm liking the idea of having both combined more and more. In my original post I said I don't need a charging system but I am leaning more and more towards an electric start and lights, as well as possibly adding glow plugs/intake heater. Any one know a place to get a complete used generator for cheap and who makes hyd. pumps with through shafts?

one think to keep in mind is that some / most pumps are not meant to be side driven it puts too much strain on the pump shaft that why they do them in line so make shear you pump can handle being side driven. would like to see how this turns out i wont to do that to my 3J D2 similar but a belt drive will not hold the hp need. so i guess a in line pump set up for me.

I have a D-2 with hydraulic pump attached to the generator mount. It is a (CW) clockwise rotation and has 9+ stamped on it. It has more than enough flow for one cylinder on a disc. Here are a few pictures. Gary




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