Installed abou 8 years ago. Was told only to use WD 40 on the rails
etc. not the heavier "aluminum "grease. Now when it goes thru its
closing cycle it starts to surge in fits and starts, back and forth,
one side then the other, with increasing noise as it does so. As well
when it stops there is often a small 1/2 inch gap left at the bottom
that a push with my foot resolves. Is this a lubrication, alignment,
cable or perhaps other problem anybody have any suggestions info,
thanks Doc