I was having trouble getting past the Passkey 3 system. It would run for a few seconds and then lock itself out on the security system so I found a shop in Atlanta that will delete the VATS and program the PCM to accommodate the 4T80 settings. Sounds like he knows what he's doing and I think he's on ...

I still have a few things to do but everything is wired up and it all pretty much matched the Caddy harness. I couldn't find a Bonneville harness in the boneyard but I did find a 2001 Lesabre and it was identical. All the wiring plugs matched up to the Caddy and according to the pin out diagrams for ...

Could not find a useable Bonneville wiring harness at the boneyard that hadn't been cut somewhere but I did find that the 2001 LeSabre forward wiring harness was the same and found one of those. Also took the front engine mount which looks the same as the Caddy and the oil filter adapter which is at ...

Yeah, I'm going to stick with the Bonneville PCM and probably have some programming done to accommodate the 4T80. I'm going to the boneyard to get a 2000 Bonneville engine harness, do you know if the 1999 PCM I have is the same as the 2000 or do I need the newer one?

I got the engine mounted to the trans today, just had to re-drill the flex plate for the four bolt converter and re-drill one bell housing bolt. Other than that, it bolted right up to the 4t80. I'm committed to making this work now because the guys over on the Cadillac Owners website keep saying "It ...

After looking into this some more I'm wondering if it would make more sense to use the Caddy PCM and have a tuner drop the 3800 parameters in place of the Northstar? I'm going to go for using the 4T80 so the shift parameters, VIN # and VATS info in the Caddy PCM would already be correct. Or would it ...

That would be great; I was hoping it would work out to use the caddy trans.

I am definitely interested since I already have the correct chassis mounts and good axles, plus I know the trans is in good shape. I read a couple of articles saying you had to re-drill the flexplate and the two lower engine mount holes plus grind the tab off of the lower right side of the bell ...

Wow, didn't realize the differences would be that much in just one year. I guess a trip to the boneyard is in order to find a wiring harness. I'm thinking I can make the radiator work. So the side cover mount on the trans is the one by the rack n pinion?

Thanks for the help!

I'm just starting on this swap using a 2001 Seville STS and a 1999 Bonneville parts car. Did you guys that did the swap use the 4t65 or the 4t80 trans? I have both and trying to decide the best route to go. I'll be using the Bonneville ECM and engine wiring harness. It looks like if I use the 4T65 I ...