2000 Bonneville TransmissionS?

I have a 2000 bonneville and the transmission finally gave up after 249,000 miles ... sheesh you can't buy anything that lasts!! I installed a used engine in it @148,000 miles after a rod broke on the original engine and have since put 100,000 miles on it. After pulling the transmission and checking numerous sites my tranny is a 2.86 ratio opt FQ3 tagged with PAB ... My question is ... I have a 3.05 ratio opt F83 tagged PCB with 89K on it ... aside from the obvious ratio difference ... will this tranny work electronically on my car? Or will I have to take the car to a mechanic to update the computer with a TechII for the different transmission, additional dollars I don't want to spend? I have found several PAB trannys in the area that I am sure will be a "drop in" fit. Any help would be appreciated ... thanks in advance.

The newer cars will get pissy with a different ratio trans, the PCM will need to be flashed for the 3.05 gear ratio... On the older OBD1 cars this really was not a huge issue as the trans would function but you would hit fuel cut off on the top if you weren't careful.. All we used to do was get the chip from the donor car...

But your situation is not the same, and the PCM in your car is much smarter, and does not use a chip that can be swapped... Reflash is the only method...