Why was the rearend ratio on the 6-speeds changed from 1993 to 1994?
The only reason GM went to the 3.42 rear differential for all the 1994 and later 6-speed models (versus 3.23 in 1993) was to accommodate CAGS. A lower rear gear ratio would bog the engine down too much for a 1st to 4th shift. Note the transmission gears between 1st and 4th were also made much closer mostly due to a taller 1st gear for CAGS. If you combine both the transmission and rear gear ratios, the ’93 6-speeds equipped with a 3.23 actually have a higher overall ratio from 1st to 3rd.
