Automatic Transmission Shifter Housing Film
My '97 NAS D90 has an automatic transmission. The housing that has the shifter in it, (P,R,N,D,3,2,1), has a black "film" that slides back and forth, to cover the "hole", that would otherwise show as the shifter is slid back & forth for gear selection. My original one failed back in 2002, but I figured it was due to dust & dirt invasion, so I lived with it for a few years because a replacement was over $100 !! Then somewhere I read that the unit for the RRC's would fit with a slight modification (saw off the plastic studs on the mounting base. RN sold these units for about $60, a much easier price to swallow, so I bought 2.
This past Sunday, I noticed that more pressure was required to move the shift lever. Upon closer examination, I could see that the film was "bulging up" as I pushed the shifter back & forth, then the shift ball on the film popped out of the film, now it needed immediate attention before the film was to tear. So before the thing totally failed, I decided to take it apart & clean it, thinking that it simply had a build up of grit & dirt, causing the film to "bind-up".
In order to get to this thing, you have to remove the center console, dis-assemble the shift handle, then you can remove the unit. Once in hand, there are 4 other screws holding in the "film unit" into the main housing. Now the film can be inspected and cleaned. What I found was the real cause of the film failure, burrs on the plastic housings that the film is in contact with, SHARP burrs. These burrs actually dig into the film, over time, and cause a progressive wearing of the film until it eventually binds up or tears.
I examined my new spare and found the same sharp burrs on it. Pre-designed failure. So using a box cutter type razor blade, I removed all the burrs in contact with the film, rounded & sanded those surfaces. I then CAREFULLY used some Rain-X on a cotton swab on those de-burred surfaces (Rain-X has silicon in it, and alcohol which will further "slicken-up" these surfaces) and reassembled the existing unit. Shifter slides smoother than it ever has. Also, while you're in this deep, be sure to oil all the moving surfaces of the actual shifter mechanism.
If someone knows of a "higher end" unit other than this cheesy "film" unit (maybe from a D2 or RR) please chime in. So if your replacing a failed unit or want to extend the life of your current one, a de-burring session is in order.