01 trooper 2wd v6 auto tranny problems
 

Have a 2001 Trooper 2wd v6 auto, torque converter shudders on lock up. Up & down shift. Tranny rebuilt at 100K, now has 140k. Level O.K. Shifts smooth otherwise. Mileage is only 12 mpg. Recent complete tune up. What can I check, local tranny shops awful