Start at the front and work your way back.The shift lever cable is housed in spiral steel cables and it is then covered/shrouded in a hard plastic coating(it is black).The spiral cables corrode,blow the outer plastic and make the shift lever hard to move.Look at the cable.If it has swelling in it,corrosion has started,You may find the plastis casing split.Either way,you can get away with replacing it buy getting lube down that cable.Start with wd40 and go from there.If the spiral cables havn't broken and only the casing is gone,you will get some use for a while.Get someone to twitch the lever back and forth and you feel the cable.You will often FEEL where the binding is happening.Hope this helps