Two disparate things here:
1) I believe rbmcmjr is correct. As I have heard it, S&W's lifetime warranty started with models in the spring of 1989. This is what I have reliably heard; you should call S&W to verify. I do not believe your gun is covered.
2) The early 686 models were subject to a factory recall because of primer flow-back caused by an improperly sized and fitted firing pin bushing. You should also call to see if you have one of these models. This is an open-ended recall, regardless of the Lifetime Warranty. If your model is affected, they will send you a shipping label and return the gun to you so modified. Look in the yoke cut of your gun and see what it is stamped. If it is 686 without a dash, or "686-1" and there is no "M" stamped in there (for "Modified" for the recall), your gun may be one of the affected guns. I think 686-2's were covered, also. I know my 686-4 is not involved.
Not all early 686's do this. I have one (a 686 "no dash" from around 1984), and it works flawlessly, so I have not bothered to send it back. Should it act up at some point or it need a "free round trip" to Springfield for some other purpose, I can call upon that recall.
Call S&W CS tomorrow and give them your S/N and ask about the recall and the problems you are having.
