My local Kubota mechanic walked me through troubleshooting with a multimeter and the problem ended up being a blown 5-amp fuse. If the fuse is blown, the diverter will default to the up/down mode only - you won't be able to rotate the chute. The wiring on my LX3310 went from the toggle switch (which selects up/down or right/left rotation), under the floor mat and up to the fuse box. Along that wire somewhere there is supposed to be an inline 5-amp fuse. Mine was hidden under the fuse box which required me to remove the 2 bolts on either side, and I found it zip tied to the wiring harness underneath. I replaced the fuse, fired her up and good as new.The plug from toggle that goes into diverter was the issue. Plug has insert that pops out with 3 wires. Ground wire had detached. Reattached and works like new. Also fuse for this oper. Is under dash on this model. Newer models have fuse under boot on hydraulic lever.
Since then, I have blown 2 more of the 5-amp fuses. So it may something that's causing it, or I just bought a bunch of crappy fuses (the most likely scenario). Or maybe it needs a 10-amp fuse?