Your right they have SCH drive boxes instead although I have heard of several in this area that broke loose from the head frames. That was a big improvement for JD to make though, since their own wobble box self destructed on 30' heads pretty regularly. Any way you go pushing a flexing sickle 30' or more is alot of strees. NH's wobble boxes held up pretty well with 20-30' single sickles, at least as good as Deere's did but the mount on the NH was way too light to change them to a single sickle.