I'm not a manual guy but I would try the fluid first then check the clutch and it's components to see if they've gone bad at all to fix the shifting problem. As far as the shaking in the steering wheel goes I had a similar problem with mine check your tires there may be dry rot or a tear in the inner wall (mine) you will probably need them all replaced since they've been sitting and get an alignment too that also may be some problem... And since its been sitting do the full tune up.. spark plugs, filters, maybe a new belt, and all the other little things to get it running more efficiently to lower the risk of future problems with it