I had hoped that I could just replace the sliders, but after ordering them from owfinc.com, I found that there is a small tang broken off the bottom of the zipper guide that prevents the zipper pull from sliding off. I'd hoped that I could put a zipper stop clamp at the end, but it is too bulky to allow the bottom pull to slide down far enough to insert the opposite zipper guide into the double pull assembly and start the zipper.
Such a simple break is going to cost $60-$80 to replace! :-(
Oh, and to the previous poster (Unfortunately with BPL's limited functionality forum I can't see your post while typing this...), I have often taken advantage of the manufacturer's warranty/ordered replacement parts for non-REI items purchased at the garage sales, but since this is an REI jacket, REI is not going to provide further warranty service--they already satisfied their warranty by replacing it the first time.