i thought this was covered, but couldnt find it-anyway, i was looking at an add for the TCI 6 sp auto, they use a 4l80e case, and somehow add 2 extra gears-starts out as a lower first gear-i would imagine its priority to their controller, got to be an expensive setup-just curious how they got the extra gearing in the case

 

Here's the thread on it. The extra gearing is done with valve body changes and TCU changes.


https://ls1tech.com/forums/automatic...peed-auto.html


http://www.tciauto.com/WhatsNew/

 

They basically do this: 1st, 1st and OD engaged, 2nd, 2nd and OD engaged, 3rd, then OD. The lower first gear is accomplished by a different planetary setup, available for any Th400/4L80E. The 6 speed is all in the valvebody/electronics.