don't work

When i shift in to mid range it acts like its still in neutral..... high and low work fine and im good on hydraulic fluid, what is going on?

I've had my 1975 DB 995 for 26 years. I have a Loader on it. I was Roto Tilling this AM. After pulling the Hand clutch to engage the PTO, I tilled approx 30 yards and then tried lifting the tiller. It would not come up out of the ground. I switch Hydraulics to LOADER, it would not raise...