working on my 384 Leyland-Ser# 84N/303333/Z 153245, I had tractor given to me and when working on it, found trans and rear-end gears and bearing where bad. Got another complete (so I thought) rear/trans for it. Ran into few issues with the two units. My original draught controls has three linkages to operate hydraulics/draught. The other one has two linkages and did not have a hydraulic pump with it. My questions are, 1. which one is the newer unit and is it better. 2. are the hydraulic pumps different between the two. 3. cant either unit interchange as long as there complete. 4. how do I plum the units to get external hook up to work cylinders. My goal for this tractor is to have dual hydraulics to mow and run round baler. I do have an manual and I also see there is a diff, but can not find anything about hydraulic pumps. Is there any web sights on looking up ser # for more info for this tractor.