Hi im in a real bind right now. My 98 gtp Trans has taking a dump due to a really bad output shaft seal that was caught to late, so looking thru the junk yard I found a wrecked 2004 grand prix 3800 n/a with low milage. so my question is can I use this transmission to replace my 4t65e-hd, while swapping the differential and cover from the HD trans. I read something about the gear ratios being different as well. Could I get A zzp or intense pcm flash and request the gear ratio changed to 3.29 to match the transmission ?