I have a L345 DT 4x4. I added a single rear hydraulic port. It was done at my local ag shop. They tapped the feed and return lines into the large hydraulic reservoir on the right side of the tractor. A single throw switch was located in the cab of my tractor. It cost about $500 for this conversion, but it was done right and works great. I think the cost was equally split between the shop labor rate and the parts needed for the job. The hydraulic hoses had to be custom made for size and routed through the lever. It was about 23 years ago that I had this done, so my memory is fuzzy. Not a job I would have attempted myself, as it required expert knowledge, the right tools and the ability to fabricate hydraulic hoses with the appropriate end fittings in the shop.