The 4T65E is a box of problems for me. I have had six vehicles with this Pandora's box of gears and each suffered the same fate. However, I finally love one enough to NOT want it gone. My 02 SS monte is in trouble guys. Recently the forward engage band snapped in the trans, and I have to shift like a manual without a clutch, which is never a great idea, and even a bad idea when it is your only transportation, which is the case for me.

I know that the 4t65e has many variants, with different switch types, wiring types and cooler line connection types, along with a myriad of gear ratios. I have managed to locate two possible donor cars with good transmissions. One is a 99 Monte Carlo with the 3100 engine, one is a 99 Lumina with the same series 2 3800 as my Monte. Can anyone here confirm that either of these will or will not swap into my baby? I understand that supposedly one can have a dealership flash the computers to make a car recognize and accept a different gear ratio, but I live in the middle of nowhere, and to be honest I cannot afford to have it done, so I need to make sure the swap would be a basic plug and play. I can change the thing myself, I can swap the switches and possibly the line connections if i can locate the pieces, but the gear ratio is what scares me the most.

Has anyone here ever done a similar swap? I am completely alone in this job, as i cannot afford to hire help or pay someone to do this, and I simply cannot afford to buy a new trans. Any help or hints are appreciated, and yes I posted a similar thread in the trouble shooting area, so if that breaks rules i do apologize and will remove one of these. Please if any of y'all can help i will be forever appreciative to everyone here....

 

I'm pretty sure either of those would work fine for you. The gear ratios didn't change on Monte Carlos. A lot of that had to do with the other cars that also got the 4t65s, I don't believe any Monte Carlo besides the supercharged ones received a different gear ratio.