TH125C Ratio differences?
Posted: Fri Sep 06, 2019 2:49 pm
Okay, yes I spent some time 'Search"ing, not finding much relevant to my question though -still some interesting topics come up here
. I suspect it is here somewhere, but really, is fresh posting on this forum a bad thing now?
Here is my question, and I hope someone on here with knowledge and an interest in sharing such would like to chime-in:
Is there a difference in the gear ratios in the TH125C 3-speed automatic from year-to-year or from engine-to-engine? Specifically, would a '90 3.1 utilize the EXACT SAME gear ratios as, say, an '88 2.0? I know different GM vehicles got different ratios, but did Chevy bother to use a different FDR for the smaller 4-bangers?
Part two to the question is torque-converter stall-speed, any difference there?
I've glanced outside the forum here too, and found data suggesting both the '90s 3.1 and the older 2.0 used 3.18 ratios, nothing concrete though, again, not making it a career to search for this.
Thanks.

Here is my question, and I hope someone on here with knowledge and an interest in sharing such would like to chime-in:
Is there a difference in the gear ratios in the TH125C 3-speed automatic from year-to-year or from engine-to-engine? Specifically, would a '90 3.1 utilize the EXACT SAME gear ratios as, say, an '88 2.0? I know different GM vehicles got different ratios, but did Chevy bother to use a different FDR for the smaller 4-bangers?
Part two to the question is torque-converter stall-speed, any difference there?
I've glanced outside the forum here too, and found data suggesting both the '90s 3.1 and the older 2.0 used 3.18 ratios, nothing concrete though, again, not making it a career to search for this.
