1997 Mercury Grand Marquis Owner Guide 1st Printing - Page 161

Traction-Lok Axle (If equipped) This axle provides added traction on slippery surfaces, particularly when one wheel is on a poor traction surface. Under normal conditions the Traction-Lok axle functions as a standard rear axle. Extended use of other than matching size tires on a Traction-Lok rear axle could result in a permanent reduction in effectiveness. This loss of effectiveness does not affect normal driving and should not be noticeable to the driver. RWARNING To avoid injury, never run the engine with one wheel off the ground, such as when changing a tire. Traction Assist TM (If equipped) Your vehicle may be equipped with the optional Traction AssistTM system. This system helps prevent wheel spin in order to improve tire traction and is an especially useful feature when you drive in hilly areas or on slippery, icy or snowy roads. Traction AssistTM works automatically by rapidly applying and releasing the brakes to prevent one or both of the rear drive wheels from spinning during acceleration. During the Traction AssistTM function, which most often occurs during low speed acceleration on slippery surfaces, a noise may be heard coming from the engine compartment. This noise is created by the ABS pump and is normal and may last for a few seconds during the acceleration of the vehicle. 161