I had a similar issue when I installed 13" rotors and larger calipers on the front. It seem'd that the calipers were on the wrong sides L/R. Cleared up when I put them on the correct side. Seemed to happen when turned the wheel and backing up. I know you didn't mention a brake conversion, but thought I'd toss it out there just in case. Sounds like you went through a big chunk of the front suspension.
Xcal2-tuned by Lonnie* Jmod kit by Darrin/Alan* '04 Marauder T/C*2002 GT MAF/airbox/intake tube* '04 explorer PI 4.6L/P&P by steenracing* Comp Cams - XE262AH* Accufab Plenum/ 75mm Throttle Body* 30lbs. injectors* 190lph fuel pump* 180* T-stat* Motorcraft 22C's* Steeda U/D pullies* JBA Ceramic Coated Headers* Aluminum Driveshaft* FRPP Aluminum pumpkin 3.73*
not installed yet:Suspension stuff: JL rstb/lower engine cradel brace/subframe connectors* KB FSTB* MN12Performance solid engine mounts/trans mount/poly crossmount bushings/IRS Diff bushings/Rear Cover Brace*RE6 Slam Specialites bags in the rear* Viair 400C compressor* 5gal Firestone tank* (8)Parker 1/2"valves* Dakota Digital Guage