1. what do you mean: 'only top off when need be.'?
==>> only when fluid is low, you add the fluid to bring the level up to correct mark
2. No shaking when waiting for trafic light, what does it mean: tend to stall? Sluggish in picking?
==>> tend to stall - tendency engine dies
==>> sluggish in picking up - dragging feeling during accelerating
==>> did you mean you feel the steering wheel shaking when you are applying brake when speed is over 40mph? if this symptom is only during braking, it indicates you have a wabbled front rotor(s). if it shakes whenever speed is above 40 miles, there could be many possiblities contributing to the problem, such as tires out of balance, bubles on tires, or front end bushings are cooked (front end rebuild is in order).