In a message dated 2/29/2012 5:01:44 P.M. Eastern Standard Time,  
d.rotblatt@VERIZON.NET writes:

Does  anyone know what i'm talking about, and if so, is it something that 
acts as a  lubricating/wear strip in the track?  

If it is a normal piece,  how thick is it?  I can get a piece of 1/16" 
nylon on amazon and cut a  strip to put in there if it's not too  thick…

Thanks!

i have a box of those  somewhere....  every late model van had  them..