Yep, the Chevette economo box was a 3 spead, it was the precursor to the 4L30E, it's was explained to me, and shown in a static museum display; I was shocked; I will photograph; the same base tranny evolved to be used in other vehicles; at the truck level, the addistion of the small forward pain thats easy to come off was added amd this gave the 4th gear; so I don't mean the GM 4L30E was in Chevettes, it was not, but the successors of the base tranny are what we now have; electrical controls and, over drive where added; and some things that should have been beefed up for 4WD were not, and thats where our premature failure occurs; overhauls should be done at 75K; or, more expensive parts not in a Master OverHaul kid are needed such as the ENTIRE OUTTER CASING!!!!!! How has a tranny that I can gut for the case! Help!