Short answer is no. You'd have to dig into the side of the case and convert various internal parts/wiring to make it work. You should be able to find an appropriate transmission at a local yard for $200-300 on www.car-part.com and possibly recoup something from the other one via classifieds/marketplace/etc.
Good Samaritan work sometimes isn't perfect, and these things happen. Every week I have to remind people here that just because it bolts together doesn't mean it'll fire right up without accounting for the difference in years/models on certain things.
The tag on the back of the transmission is the key for this, and if you post a picture of your old one's tag & the replacement's, in conjunction with the year/make/model of your car (I see it in the title), it helps more clearly communicate what you need.
Some info here, although it takes time to understand the details:
EDIT - after skimming the FastFieros link, I can clarify what your car came with...
RPO: MN7 (4T65e-HD version supercharged cars get)
Model: 9FCB
Platform: C (Park Ave's were called "C" body due to legacy from '91-'96, but was essentially a G-body from '97-'05 like the Riviera/LeSabre, etc.)
Carline: B (Buick)
Looks like the only version that year to come with the Internal Mode Switch (more and more 4T65e's got it in later years, until they all got it by ~2003, along with some other internal updates that year). You could basically swap in any '98-'02 transmission with the IMS, but note that fittings for the transmission coolers started changing to the "quick-release" style in 2000-up cars.
Good Samaritan work sometimes isn't perfect, and these things happen. Every week I have to remind people here that just because it bolts together doesn't mean it'll fire right up without accounting for the difference in years/models on certain things.
The tag on the back of the transmission is the key for this, and if you post a picture of your old one's tag & the replacement's, in conjunction with the year/make/model of your car (I see it in the title), it helps more clearly communicate what you need.
Some info here, although it takes time to understand the details:
EDIT - after skimming the FastFieros link, I can clarify what your car came with...
RPO: MN7 (4T65e-HD version supercharged cars get)
Model: 9FCB
Platform: C (Park Ave's were called "C" body due to legacy from '91-'96, but was essentially a G-body from '97-'05 like the Riviera/LeSabre, etc.)
Carline: B (Buick)
Looks like the only version that year to come with the Internal Mode Switch (more and more 4T65e's got it in later years, until they all got it by ~2003, along with some other internal updates that year). You could basically swap in any '98-'02 transmission with the IMS, but note that fittings for the transmission coolers started changing to the "quick-release" style in 2000-up cars.