My midland gearbox died and I'm going to get a rebuilt one from Mini Gearbox Ltd. Wish I could do the Getrag swap but I just don't have enough money. Anyhow my question is, those of you who have went back with a Midlands but did the fluid change regularly, how many miles do you have on you gearbox now? or how many miles did you get on your rebuilt gearbox? How often should I change the gearbox fluid to try an extend the life once I get the rebuilt one put in?