It feel strange to read rcParams here in `Ticks` if it is called `axes`, and is already used in `axes.py` . Moreover, the value of `gridOn` seem to be passed around  [here](https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/axis.py#L1605) and commenting all this block does indead keep the wanted behavior. I propose to change those rcparams to `<x|y>tick.<major|minor>.grid = Bool` to be consistent with the all the other parameters.... unless I'm missing something.