Having spent two of the unhappiest hours of my life filling my SV's Type 9 gearbox with oil (well, much was spent trying to refit the fill plug - there's a cross member which makes getting the plug back in all but impossible unless your fingers are the thickness of a lolly stick - but judicious use of a cable tie eventually worked!), ten years ago when I built my 7, I reckon I ought to replace/refresh it. I will remove the plug and pump the old oil out. As I doubt I'd be able to get it all out, there is the potential of some contamination with the new oil. Is it then worth running briefly with some cheap oil by way of a flush before replacing that too or would it OK to go straight to the good stuff? Also, any tips to make the whole (potentially repeated) process less of a 'mare?