If your chassis "flexed" enough to bend a drive staft you may have a permanent bend and it may be at an angle. Your chassis could be slightly bent at an angle ... tweaked. Remove your wheels, place the chassis on a flat surface and check the flatness. Also check the chassis tweak on a tweak board.
"Yellow Jacket" Mugen MTX-6, Picco Torque
TeamNITRO RC Club, Lynwood, Illinois