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<blockquote data-quote="PoManNox" data-source="post: 29024" data-attributes="member: 8300">Best I can tell from online, the old 6spd 6T45's gear ratios range from 4.58 (1st gear) to 0.75 (6th gear)The new 8spd, 8T45 is 4.69 to 0.62.Not an earth shattering delta between the two from low end to high end, but the shorter steps to get to 0.62 is where the 8spd &quot;should&quot; gain some fuel economy.I love the 6spd in my 2021 w/ 1.5T.&nbsp;&nbsp; It's perfect for 6 gears.&nbsp;&nbsp; IMO, it's not enough engine to squeeze two more gears into.My guess here is GM programmed it to hit and hold 8th only in absolutely perfect conditions to save the unit from constantly flip/flopping in 8-7-8-7, on top the torque converter potentially having to go in/out of lockup in the process.&nbsp;&nbsp; People would complain about that as well.On top of that, demanding higher torque at low RPM from these little 1.5T's isn't going to do them any good. Spark knock, LSPI, etc..</blockquote>

[QUOTE="PoManNox, post: 29024, member: 8300"] Best I can tell from online, the old 6spd 6T45's gear ratios range from 4.58 (1st gear) to 0.75 (6th gear) The new 8spd, 8T45 is 4.69 to 0.62. Not an earth shattering delta between the two from low end to high end, but the shorter steps to get to 0.62 is where the 8spd "should" gain some fuel economy. I love the 6spd in my 2021 w/ 1.5T. It's perfect for 6 gears. IMO, it's not enough engine to squeeze two more gears into. My guess here is GM programmed it to hit and hold 8th only in absolutely perfect conditions to save the unit from constantly flip/flopping in 8-7-8-7, on top the torque converter potentially having to go in/out of lockup in the process. People would complain about that as well. On top of that, demanding higher torque at low RPM from these little 1.5T's isn't going to do them any good. Spark knock, LSPI, etc.. [/QUOTE]

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