As above really! The Haynes manual says to refill till it flows out of the hole and then remove just over half a litre? Is this right? It sounds a bit odd to me. 

That is indeed the procedure that Ford prescribes.

Another method (which I personally prefer) is to drain the gearbox completely and fill it with the correct amount of gearbox oil. The Ford B6 gearbox has an oil capacity of 1.7 Litre.

When draining the transmissioin oil you should be aware that this transmission use a very low viscosity oil. When removing the drain plug the oil will spray out pretty fast (and far). To avoid a real mess you should be prepared.

I found that out the hard way 😂 thanks for the tip though, I’ve only ever known to fill until it dribbles out! I’ve drained the fluid as I’ve been doing an engine replacement so driveshafts out and drain plug out, so I should be good to just refill with 1.7 litres then? 

Refilling the gearbox with 1.7 Litres of the correct gearbox oil  when the gearbox is completely drained is perfectly fine.

Despite being "filled for life" the Ford Durashift B6 gearbox (Getrag 6MTT250) really benefits from an oil change. Because of the small oil capacity of this gearbox the transmission oil deteriorates/contaminates pretty quickly. The Ford Durashift B6 gearbox uses the same transmission oil as the powershift transmissions. This is a very low viscosity oil that is primarily designed to reduce emissions and fuel conssumption. I recently changed the gearbox oil on my own (low mileage, only 35.000 KM) car and it definitely made a noticeable difference.

 

Bit of a revival sorry. Where are the fill and drain plugs on the B6 gearbox please as I fancy a do at changing this myself.