Hi.
In keeping with many of us my M20 has a stupid gearbox oil leak (bet you've never seen one of those then).
I spoke to a guy who made a differential for me and he uses grease, instead of oil, that should last a normal lifetime.
Yesterday I spoke with a local friend who is seriously into our oldies and he actually keeps this stuff on the shelf and uses it in old gearboxes, Quote " I have used it for years with no ill effects".
Its a case of drain the oil--melt the grease and pour the relevant amount into the box. With M20 he suggests taking off top plate to make pouring easier. Then, as it cools, it re-assumes it grease properties.
Because of its viscosity it doesn't "track" like ordinary grease does. So I'm seriously thinking of giving this a go.
Anyone with experience, I would like to hear about it.
Mike