So I have a three speed R11 on the back of my 312. In breaking down the tranny, we determined the previous owner had smoked the overdrive portion of the tranny (probably not knowing you have two fluid compartments). The parts can be a very difficult to even find to rebuild the normal tranny, but the overdrive portion is even harder. So my two questions are 1) does anyone know who may carry the overdrive parts like the Planetary gear etc ?2) What issues would I have to consider in just running without the overdrive engaged (basically pulling the planetary out)? 

might try here  I know people who have bought old trans parts but don't know what they have in OD.

Try here:

http://www.vanpeltsales.com/

This guy is a Ford transmission and overdrive specialist.. Mike Miles   9310alloy@gmail.com  414-690-2748

Where are you located  Carl

Mike Miles is in a Milwaukee suburb. He has stuff nobody else has available..

Thanks I will give them a call!

Thanks I will reach out to him.

I am located near Houston.