Hello Benj:
Is the F-30 now called the F-3002?
If so, then we are using the same engine and a G-40 Gearbox.
Mine has approx. 270 hours on it and no cracks.
On mine there is an adapter which mounts between the gearbox and engine. You can remove the upper allenhead bolts and remove the gearbox and clutch drum.
The centrifical clutch then can be removed and then the four 19mm nuts can be removed to take the adapter off.
The clutch is larger than the diameter of the opening, therefore must be removed before the adapter can be removed.
Call Matt at Recreational Power and see what the adapter costs?
RP&E number is 419-585-7002
ps:
haw about some pics