Elmo - A couple of other things to look for when you inspect your springs:
Truck sagging/leaning to one side (possibly worn shackles/bushings, but also caused by sagging springs)
Cracked individual spring leafs (even one is enough to consider replacement)
Gouging of leaf springs into the adjacent leaf (metal to metal contact wearing a groove where the smaller leaf end meets the longer leaf)
If you do replace them, be sure to do them in sets (both front, both back or all around). Replacing only one side will lead to some less than fun driving experiences.
