Anyone know how to slow the top speed of truck down.Its a sx controlled ge system.Option 11 ,12,13 on lx 12 reverts back to default of 0.Its also adjustable from dash.13 is for service and overheat.11 said to contact MCFA first.Pin P1-12 must float or speed limit deactivated.I have done pulled pulg and undone P1-12 still didnt slow truck at all.We have a call in to see how its done but its buging the crap out of me.Any help will be appreciated.