You have peaked my interest with filling at the shifter because I find that sometimes I can not get 1st or reverse to engage during heavy activity such as driving then moving around in parking lots or backing into loading docks. I was wondering if there isnt enough oil there to keep it lubricated during that time as I have no trouble with getting them to work when its cool. Have you had any such problems? And what lead you to believe that you needed to add more than what teh fill plug allows?