Its not mentioned as a New Holland anywhere in the manual per say. All decals and stickers etc on the tractor are strictly FORD. I think it was a later year model change when it went NH. I do not have shuttle shift. I think the biggest differences is style of hood and operators deck, and transmissions. I have a 3F+1R, and then 4 different ranges in the range selecter for a total of 12 forward or 4 reverse speeds. Also the ROPS is of different design. IIRC the ROPS on a 1715 is sort of oval where the rops on a 1720 is U shaped and bolts on on top of the fenders to a reinforcement that is attached to the rear axle and final drive.
I have only had created problems for the most part with mine. I find the fenders to be awfully soft, and it does not take much to bend them. Thats a big problem with me, as we have some super strong vines, and all it takes is a vine between the tire and fender and fender is bent. I reinforced my fenders with 1/4" aluminum plate riveted inside the fender well, and sealed with aerospace rubber sealant. It made a difference, now I don;'t have to worry about them getting bent anymore. Other than the clutch problem on the face comming off when it stuck to the flywheel / pressure plate, and a bad iginition switch all I have done to it is grease oil and fuel. I do need a new exhaust pipe and muffler as my son broke the other off ona low hanging limb, and I instyalled a muffler I picked up from the Ag supply for $20.00 on it and it sounds like a D-8 dozer. I sure miss the slight whining, easy going sound it made, almost like an electric motor with the original exhaust sysyem . How many hours is on your machine. Mine is pushing 800 and still uses no oil or showing any other signs of being worn out anywhere.
My starter is starting to act up like a bad bendix drive, so I may have to try and start it 2 or three times if it don't catch on the first try. My Ford dealer told me the bendix is not available seperately, only as a complete unit on a new starter............I hate to think what one of them would cost. When it does finally go, I will park it on an incline and catch it in gear ;-)