* Broken or Failing Rear Springs: This is the most likely culprit. Springs can break, sag due to age and fatigue, or lose their ability to support the vehicle's weight. A broken or weakened spring will result in a lowered rear end and a much rougher ride.
* Worn-out Shocks or Struts: While springs support the weight, shocks/struts control the rebound and dampen the oscillations after hitting a bump. Worn-out shocks/struts will allow excessive bouncing and transferring more impact to the chassis, making the ride harsh.
* Air Suspension Problems (if equipped): Some Expedition models have air suspension. A leak in an air spring, a faulty air compressor, or a problem with the air suspension control module can cause the rear to lower and lead to a rough ride. This is often accompanied by warning lights on the dashboard.
* Overloaded Rear: If you've been carrying heavy loads in the back consistently (cargo, towing), it can cause the rear springs to sag permanently. Even if the load is removed, the springs may not return to their original height.
* Rear Axle Issues: Less common, but possible, issues with the rear axle itself (like damaged bushings or a bent axle) can affect ride height and comfort.
What to do:
1. Visual Inspection: Carefully examine the rear suspension. Look for broken or obviously sagging springs, leaking shocks/struts (oil stains), and any other visible damage.
2. Check for Warning Lights: If there are any warning lights illuminated on your dashboard related to the suspension or traction control, this is a strong indication of a problem that needs professional attention.
3. Professional Inspection: The best course of action is to take your Expedition to a qualified mechanic or Ford dealership for a thorough inspection. They can diagnose the exact problem and recommend the necessary repairs. Don't attempt major repairs yourself unless you have significant mechanical experience.
Ignoring the problem could lead to further damage to other suspension components, potentially making the repair more costly in the long run and impacting your safety.
