I'm trying to get a new remanufactured automatic transmission switched out for my current, failing one. I didn't realize there can be so many small differences in the same model transmission, and I was hoping you guys could let me know what'* compatible with my car as it is a little uncommon.

Car Info: 2006 Chevrolet Malibu Maxx SS (3.9L) -Powertrain- Engine manufacturer: GM High Value LZ9 3900 Cylinders alignment: V 6 Displacement: 3880 cm3 / 237.2 cui -Drivetrain- Gearbox: GM Turbo Hydramatic 4T65-E

...and while I see many of these 4T65-E'* around, (with the same exact gear ratios), the main difference I'm seeing is my car has a final drive ratio of 3.69. I can't find any others with the same final drive ratio, most of them are 3.29. Is it necessary that I find a tranny from a car with the same engine size and same final drive ratio? If you need any other info please let me know, and thanks so much for reading.

Link to detailed specs of my vehicle: 2006 Chevrolet Malibu Maxx SS (since mid-year 2005 for North America U.*.) specs review

Remanufacturer should be able to get you the right gear ratio.

If you're looking for a used transaxle you can certainly run a different gear ratio, get the PCM reprogrammed, and live with the performance consequences. I wouldn't get a used transaxle out of anything that had an engine smaller than 3.8L . Goes without saying that used transaxles are a crap shoot.