I have a 97 deville that had a bad tranny soI swapped a 95 eldorado transmission into it, now I am getting a code P0730, incorrect gear ratio, I looked them up and it appears that the only difference is the final drive ratio is 3.71 and it is supposed to be 3.11, is there any way to fix this? do i have to change a part in the transmission or can i just modify the computer to run with this newer ratio, i know that the concours uses this ratio

after much searching i have found that it may be possible to flash the pcm with the newer gear ratio