Symptoms
Rear sag, bottoming out on washboard, or the truck sitting on its bump stops once the drawers, fridge and water are loaded. Payload can be as low as 880 lb (Quadratec lists that for the 2020 Sahara four-door).
The fix, step by step
- Weigh the loaded truck at a scale first.
- Then fit springs rated for the real load: support the frame, unbolt the shocks and sway-bar links, lower the axle, swap the coils, and refit at ride height before torquing the bushings.
- For a permanently heavy build, a heavy-load kit with matched shocks is the better answer.
- Re-check the track bar and alignment afterwards.
Tools & part numbers
- Floor jack and stands
- sockets
- torque wrench
- access to a vehicle scale.
Where to buy the parts
Skyjacker 2.5 in dual-rate rear coil pair, 2018–2020 JL UnlimitedQuadratec ↗Amazon ↗
AEV N0724780AA DualSport XP 3 in heavy-load lift kit (Quadratec lists it for the JL Unlimited Rubicon 392; check fitment)Quadratec ↗Amazon ↗
JL coil springsExtremeTerrain ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Jeep Wrangler JL Unlimited parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.