It stands to reason that if your car is equipped with  a Acura TL steering rack-and-pinion  unit, you've got both a rack and a pinion. The pinion is connected to your steering wheel via a set of shafts and U-joints. When you turn the wheel from inside your Acura TL, it moves the pinion, which pushes the rack either to the left or to the right. The ends of the steering unit which has tie rod ends at each end are connected to your front wheels so the steering unit input turns them to the left or to the right as well. And that's all there is to it sort of. On lightweight sports cars, that really is about all there is to the steering unit. The Acura TL steering unit is permanently lubricated and in many cases lasts the life of the vehicle. Most of us, however, have a power steering rack and pinion unit that adds a whole new level of complexity to the whole system. This Acura TL power steering unit uses an engine-driven pump to supply high pressure hydraulic fluid to the steering unit when you turn the wheel. While this makes it much easier to turn the steering unit it also means that lots of hoses, seals, and o-rings enter the picture to contain the hydraulic fluid. On modern cars, a bad power steering rack usually translates into a leaky power steering unit. And since a leaky steering unit can't contain the fluid needed for light, easy steering, the steering unit has to be replaced with a new or re-manufactured unit with all new seals and gaskets. If a shop tells you that you need a new rack and pinion but you're not experiencing any loss of power steering fluid, get a second opinion: Most steering problems like wobbling, play in the wheel, and wandering, aren't caused by a bad rack and pinion unless they're accompanied by significant leakage.

• Rack and Pinion unit is permanently lubricated .
• A bad power rack and pinion usually translates into a leaky power rack and pinion.