In the rear, the WJ has no track bar. Instead, it uses an upper triangle and lower control arms to locate the axle forward and backward, and side-to-side. The upper triangle uses a ball joint connected to the rear axle above the rear differential. This ball joint is the worst point of wear on WJ Grand Cherokees. Iron Rock Off Road offers this bolt-in adjustable short upper A-arm that uses a 2.625-inch flex joint to locate the rear axle. But you must have at least 2 inches (up to 7 inches) of lift to use it.