I have a 99 alero 3.4L, which came out of a 01 impala, and I have replaced the tranny about 2 yrs ago, w/ 1 from a 03 Grand AM. So, my drive chain broke in the tranny, 243k miles, not bad for wear and tear,huh? Anyway, my question is; I found another 4T45e, MN5, 3.05 gear ratio out of a 2007 Saturn, 3.5L, same gear ratio - 3.05, same type - MN5, same connector 20 pin; and I was wondering if it will work in my Alero? Now I know there was a few changes in 2005 to the MN5 but only with the Malibu and G6,but no changes for Saturn till 2008. Also, I know the pcm controls the upshifts and downshifts, so if it bolts up, which it does, and plugged in my pcm should see it just another 4T45e right? My pcm has been upgraded by Sinister Performance for crisper shifts at higher RPMs not to mention my engine has been rebuilt with hydra-static pistons,so there is NO piston slap cold or not, new rockers, push rods, and cam. So, guess what I am asking is; is a 2007 4T45e MN5 3.05ratio from a 3.5L interchangable with my 3.4L Alero? That has a 2003 4T45e MN5 3.05ratio in it now.
I would call a local salvage yard and ask them, most salvage yards have interchange guides so they know what parts are interchangeable.