Jesus... I said 4l80 why on earth would anyone bother with a th400 when there is so much more tuning and other cool shit that can be done with a 4L80E?
BUUUUT just to continue down this th400 rabbit hole:
http://www.dakotadigital.com/index.c...prod/prd60.htm
That takes care of gear selection and neutral safe
http://www.dakotadigital.com/index.c...rod/prd126.htm
That takes care of speed...
What other inputs does the 6MT ECM flash need to be happy? OK ok, we may need ONE ice cube relay to simulate clutch engagement...
Instead of 'relays everywhere' it seems two universal modules should allow you to install ANY archaic trans you want. First person to swap a Lenco gets a cookie.