We have a 7930 IVT that we use for precision manure application (who'da thunk it?) Our problem with speed adjustment is that above 3mph the thumbwheel detent increments are .2mph changes. We would like to get the increments in .1mph changes up to 5mph or more. A JD rep at the Farm Machinery Show in Louisville told me it was possible to change through a port setting but he didn't have the detail. We presented the question to our dealer service mgr to send through JD. Their tecno-guru's response was a copy of the operator manual's instruction on how to roll the thumbwheel to set the ground speed. Does anyone have any technical insight into re-programming the speed increment?