It's really been a long time since I've posted on this forum but I thought I'd share some info with all the XJ fiends. I just turned 318000 on my '98 and haven't had any problems other that normal things, alternator replacement, water pump replacement etc, things that you would expect. A little over a 100000 miles ago I replaced the NSS with a cheapo off Ebay, $40. The thing lasted a long time and started acting up first with a CEL and the usual not engaging the overdrive. I had saved the original factory NSS and opened it up for some cleaning and discovered that cleaning alone will not fix the problem. If you look very closely with a mag glass you can see that the copper contacts, the long strips actually wear down and have indents in them from use. I flatboarded the entire unit, laid down some 600 grit w/d on a flat board and proceeded to sand down the contact side. When you do this the indents show up really well. I kept sanding and sanding until the copper strips showed no more indentations, cleaned the unit up, re-greased and put the original NSS back in the XJ. thing runs like new. Just thought I'd share. Cleaning is not enough, you have to even out the contact surfaces.