Originally Posted by mcgyver1467
Could be the shackles. After a while the bolts rust into the spring and frame bushings. I figured this out when I installed my lift. The factory ride was much stiffer than after I installed the lift. (87 YJ) I had to cut all the shackle bolts off to get the springs off. A buddy of mine said that that was probably the reason that the ride was so stiff before the lift.
Greasable shackles are quite a nice upgrade for that reason.
Also they keep the squeeky suspension away too.