that little piece of annoyance is there as a barrier between the two bigger pieces for corrosion protection, some metals when they corrode bond together, we probably have someone here in the forum who can explain it better than me, I was just trained to make it not happen , something about dissimilar metals aneodes cathodes anions cations salt pepper sausage and onions stainless steel and heat my first 400 didn't have one, but I kept the gearbox open pretty frequently, no chance it was going to corrode together