Is it possible that yer rear spring shackle bushings are worn? Any broken springs? How good are the shocks back there? <img src="/forums/images/graemlins/wink.gif" alt="" />

You could have someone follow you and see if the back end is pushing to one side or not when the truck is pulling. <img src="/forums/images/graemlins/wink.gif" alt="" />

How good are yer control arm bushings? <img src="/forums/images/graemlins/wink.gif" alt="" />

1998 T-100 Xtra cab SR5 2WD Auto; Roadmaster Active Suspension; Yokohama Geolander HT-S; lowered air dam; full belly pan; 4? diffuser; 11" side skirts; dual transmission coolers; 67% grill blocked; Auto-RX'd; ScanGauge II/Ultra-Gauge