Quote Originally Posted by BillBoost37 View Post
Check that the century has a 4T65E, IIRC most got the 4T60E for quite a bit longer because they were 3.1L cars vs the 3800 cars.

If your Diff was swapped that means you are currently running a 3.29 gear ratio. Any non HD 4T65E transmission plus that diff will give you 3.29 ratio. If you dropped in the HD trans and reprogrammed for 2.93, you are likely to need to tweak your timing and shift tables as well.
You are correct Bill. The Century did have the 4T60 but as of at least 2000 m.y. they were 4T65 cars.