MOD S111's had removable gearbox cross-members but it is still possible to drop it with a welded one.
I had my gearbox out three times over the years (new clutch, V8 conversion & plate rusted to the flywheel) and not once did I have to use a hoist. I removed the floor, seatbox, tunnel, props etc etc and then just pulled the gearbox back and manually lowered it onto the floor. It may have helped that my vehicle sat a little higher (extended shackles & 9.00x16's) but it worked every time for me. It also helps if you are a bit beefy as the gear & transfer boxes weigh quite a bit but I managed it without injury.
Re-fitting is the reverse of above.