After 20 min of driving, '93 Buick dies when I brake. It jerks, jerks, jerks & then dies. Restarts fine, but dies when I put it in gear.
Sounds like the lock-up clutch is sticking. Look below the battery for an electrical connector on the transmission. Unplug it and wait a few hours for the clutch to release and then drive. If the problem has disappeared leave it disconnected until you wish to get the trans rebuilt.
I agree that this sounds like the torque convertor’s lock-up clutch is sticking in the locked position, but this certainly doesn’t require a transmission rebuild.
What happens is simpler than that. There’s an electrical solenoid that sticks, allowing hydraulic pressure to keep the clutch locked. The clutch isn’t at fault, it’s the sticking solenoid. This is, in fact, the solenoid that Rod Knox is suggesting that you unplug.
What you almost certainly need to do for this common GM problem for this vintage is replace the sticking solenoid. The part is about 40 bucks or so, and takes an hour or so to replace. It’s inside one of the transmission’s pans, typically near the driver’s side front tire.