In your case, 'drive' is first gear.

If your engine is obviously rocking, the most likely cause is the gearbox mounting below and at the back of the gearbox. You can see if this is bad (the rubber breaks) by putting one hand on top of the engine (whilst it's cold, of course), and reach down to whatever you can get hold of lower, and try to rock the engine. If the gearbox mounting is poorly, the engine will move back and forth by hand. New mountings are a bit expensive but take only a couple of minutes to change with the car up on a lift.