I just rebuilt a 4T60-E from a Olds 98 (I think thats what it was) and put it in my 96 SE. Now thats its all installed I just realized the 7-prong case connector on the trans is different than the one that was in the car (the round connector above the vac modulator). They are close but not the same. Can I just get the correct connector for the new tranny & splice it into the Bonnies wiring?

Best thing to do is get the wiring schematic for both and ensure you wire it properly.

http://60degreev6.com/images/4T60E/4t60e_wiring.gif

Pretty close here

The pinouts are not always the same, one year to the next. I would get the wiring diagrams as Boosty suggested for the exact years and models of the swap. And the valving in the trans may be different, and hmmm...what about the final drive? You may need to swap the olds 98 PCM and prom to get the thing to shift the way it was originally designed. I just swap the same trans for the same trans to avoid all this. Maybe jr's3800 or mkaake can chime in with some help.

Key thing to keep in mind. Do not assume the same colors are the same hookups on different cases.

Thanks!
I did swap the 3.06 final drive from the original over to the new trans to try to avoid trouble (originally had the 3.29). Maybe I will snag the PCM and prom also when I go back for the connector-just to be safe!

The pinouts are remarkably different between my 93 and my 95.