Bad torque convert shudder on 95 eighty eight?

My brother is looking at a 95 eighty eight, he likes it and he wants to buy it. He took it out for a test drive and everything seems to work, except for one thing. Bad torque converter shudder the instant it goes into torque converter lockup. Haul it into 3rd gear and the shudder goes away. Any idea what could cause this?

Two things, one bad torque convertor, two bad torque converter clutch solenoid. If the solenoid is bad it will not lock up properly same as if the torque converter is bad. Either way it will cost at least $500 to fix.