03 Century transmission swap

[GladdyBuick]

Hi Everyone, I have a very nice 03 Century that had transmission problems. I found a 2001 donor Century with a working transmission and about 200K less miles than my 03. Unfortunately myself and my garage did not fully do our homework and did not realize that the 01 transmission is not compatible with the 03 until after we had swapped both the motor and transmission. I'm wondering and hoping that there are any instructions out there on how to make this swap possible by splicing the electrical system or some other work around. At this point I've spent about all the money I can on this and can't afford to pull the transmission out and try to replace it with another. My only options are to find a work-around to make the swap work or to scrap the Century. Thank you to anyone that can help!

 

[Dave Goodfellow]

I am no expert on this, but recently replaced the intake manifold gasket successfully on my 2002 Century. I assume you are posting this because the existing engine wiring harness is not working with the 2001 drivetrain. My belief is that the wiring harness and computer module (in the air cleaner) from a 2001 Century (or other GM car with a 3.1) would need to be swapped in to your 2003. If everything is working correctly with the 2001 powertrain, it should run and not have any OBD2 fault codes. The engine wiring harness on my 2002 is all easy to get at with just a number of clips holding it in place. This is assuming that the engine wiring harness can be disconnected, (or cut and spliced) from the body of the car. I am a Ford guy, and Fords all have connectors near the firewall for the engine wiring harness. Not sure of GM.