mine has a 17 but I was also wondering about the tranny
Well, if you can rent one or borrow one first, you can test it out. My JD (and probably yours) has a "pin" between the axle and the drive wheels. The pin shears before the tranny does. It looks like a square piece of metal. Sometimes they are known as shear pins or shear keys.
So, if you care to test it, you shouldn't lose the transmission.

=J