Had the same problem for several years. No helpful answers from Turbo or chat rooms. Finally, I voiced my frustration to an Office Max sales associate about my issues with Turbo Tax and e-filing and always getting a transmission error. He smiled and asked about the size of my file. My file was 26 pages. He immediately told me that my file was too large and that apparently Turbo efile system has a cut off limit. Large files always receive a transmission error. I just chop down another tree, print an extra copy and mail it. I know this to be true because I do other family members, their relatively simple and basic forms are sent instantly and they receive their refunds in short order. Hope this helps.
