1997 Other Buick Models ignition problems

Electrical problem
1997 Other Buick Models 6 cyl Front Wheel Drive Automatic

hello there. I've got a good question for you and we've tried to find our solution but no dice. Okay for starters, it's a 1997 Buick Park Avenue Ultra and it was in the shop cause the transmission went out so we took it into the shop for a new transmission. The transmission that was put in to replace the old one we don't know how old and what year it is. But after they put it in and everything we called and found out the car was done but the only problem was that we had to start the car from underneath touching the solenoid live and ground posts. We tried to find out how we can fix it but couldn't find no answers we asked the shop that had fixed the transmission what was wrong with the ignition and why we had to go underneath and they said they didn't even know. So as you can see we are in need of some help to try and figure out our problem so could you help out.