Also make sure your sway bar is not binding as it travels through the range of axle movement. This is definitely a problem with Addco rear bars, I don't know about the stock bar. Changing the length of the end links so the bar is parallel with the ground is the solution. Unbolt the links, pivot the sway bar down and see how far it can go before hitting the axle cover.
Lifespeed
2004 Silver Birch Marauder 130K miles
Wilwood Aero6 F, NMDP R brakes, Penske 7500DA shocks, Hypercoil 600lbs F and Grand Marquis R air springs, Addco tubular sway bars, Metco control & Watts, 31 sp axles, Stainless Works cat-back exhaust, Lidio tune, American Racing AR883 9.3" 50mm F 10" 59mm R 20" wheels, Pirelli P-Zero 265/35-20, 275/40-20 tires
Coming soon: Livernois 5.0L stroker, ADTR/Vortech V2 intercooled SC, Silverfox trans and Circle D converter