3500 SOS Trans Cooling & Backhoe Hydraulic Pump Question

I've got a 1967 3500 Ford with the SOS trans and fitted with 735 loader & 723 backhoe. Couple questions that I'm lumping into one thread -

1) The tractor does not currently have a trans cooler on it. How hard is it to fit one? As near as I can tell it came this way from the factory - no cooler in the radiator tank, no loose lines, ports, etc. Since I don't have a radiator cooler, I think an oil to air cooler would probably be the best option - easiest would be to just use an regular automotive type cooler but I'm not sure what pressure/flowrate the SOS trans cooler circuit involves and if that would work. Also, where are the ports on the trans to connect to? I haven't been able to find anything that shows where they physically are and there's no random plugged ports on the trans case that leap out at me.

This tractor is used for around the ranch work and doesn't see that much use, but it does get worked hard from time to time and the trans case gets quite hot - probably over 150* outside of the case, so I'm guessing around 250* oil temp - higher than I'd like.

2) The loader/backhoe hydraulic pump is weak. It's a Vickers vane style pump but I'm not sure exactly which one - manual lists several different options. Any suggestions on a good source for a replacement, preferably reasonably priced?

The trans cooler was stock on the 3 cylinder 4000 series S-O-S transmission, but it was an option on the 2000 & 3000 series. To fit a stock transmission oil cooler on it you would need to replace the radiator, as the trans oil cooling core was a second core built into the radiator on the ones that had it. You could probably put a separate aftermarket oil cooler in front of the main radiator but you would need one that's rated for some pressure. It is on the return side of the hydraulic circuit in the transmission but it still has somewhere around 100psi in the lines. I'm not sure what might need to be changed internally in the transmission to redirect the oil to use the external ports that the lines would connect to though.

For the front mounted pump, I would remove it from the tractor and take it to a local hydraulics shop for a rebuild. If you want a new one, find out what size and type of connectors the old one uses and buy one that has matching connections. Other than that the main difference between models will be maximum psi and flow rate. Anything above 2000psi and 18gpm should be good.

I am just about to install an original SOS
radiator in my non SOS tractor that I'm
rebuilding. Looked at it yesterday.
It has those fittings on the bottom for
the lines. If you were close I'd be
willing to swap with you. Mine is vgc and
I would expect vgc in return.

As was mentioned, go to a Vickers distributor and get a rebuild kit for that vane pump!

If it was mine, I wouldn't worry about a cooler unless the temps got over 250 as verified with a temp gauge. There's no real reason for that tranny to get that hot anyway, since it doesn't have a torque converter.

I agree with Bern. The oil cooler is probably not needed.

Why do you think that there would be a difference of 100 degrees between the outside of the case and the fluid inside? Cast steel is a very good conductor of heat and if it's been running at temperature for more that 20 or 30 minutes the outside should be within a few degrees of the inside.

Yesterday, I saw a late model 3000 in the shop at my local CNH/Kubota dealer.

It was the best one that I had seen in some time. It had all of the bells and whistles: diesel engine, PS, fully hydraulic FEL, dual (yes, 2 handles and 4 couplings) remotes , spin out rims, and S-O-S with optional oil cooler in lower radiator tank.

It was a dandy but in for work, not for sale.

Dean