Hi all: So I acquired a turfcat 628d at auction last year to replace/augment my T422d- The one I've got is from earl 2000's and runs perfect but I do not like the rear discharge deck. My 422d has a much nicer 72" side discharge that I am planning to swap out with the RD deck (and I intend to convert that one into side discharge for the 422). The deck motor on the 628 has a 3rd hydraulic line that ties into a return line to the tank- I am guessing it is some sort of pressure relief line. The older deck motor has only two lines. I am planning to cap off the 3rd line at the tee and just hook up the two main hydraulic lines. Does anyone know why the newer deck motor has the third hydraulic connection and whether there is a good reason for it? Conversely when I go to hook up the 3 hose motor to the 422, can I just cap the relief line on the deck motor?