Will a complete rear axle assembly from 1988 Ford F-150 fit 1998 F-150?
No, a complete rear axle assembly from a 1988 Ford F-150 will almost certainly not fit a 1998 Ford F-150. While both are F-150s, Ford made significant changes to the chassis and suspension components over that ten-year span. The axle width, spring perches, mounting points, and even the brake system will likely be incompatible. You'll run into significant issues with fitment and potentially safety concerns.