I haven't taken mine out since before Thanksgiving, (thanks to all the snow and salt). But even though I've never had any real problems with my 6 speed as of yet, I did notice that my tranny does operate significantly better after it warms up. It makes me wonder if they're not putting the wrong "viscosity" gearbox fluid in them from the factory.
The owners manual says it uses 5w20 engine motor oil. Like the engine, I would assume it's synthetic. If it's not, maybe it should be.