Q: How long does it take to change rear end on 2003 ford f150

The time depends on whether you are dropping in a pre-assembled (re-built or used) axle/differential or are talking about re-building what you have. To just remove and re-install the entire assembly would require roughly 7 to 11 hours depending on exactly what your circumstances are and what is re-usable or will have to also be replaced. If you want to schedule an inspection and get an exact quote please simply request complete axle/differential replacement - inspection, cost and parts estimate and the responding certified mechanic will give you a cost and a work plan based on your personal desires (e.g., new parts, used parts, related replacements and so forth). If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.