whenever i hit the throttle to pass someome up or to go up a hill, my automatic 86 berlinetta downshifts like normal, but then it'll just rev and it wont go any faster. also if i give it than normal throttle, it stays in a gear way tooo long.. any ideas? torque converter? tranny slipping? all fluids are full also..

 

it sounds like line pressure is adequate to clamp friction elements at certain loads.this would indicate improper pressures which must be tested with a gage.it also can be a worn out set of forward frictions and or other clutch pack.it is wise to remove the pan and check for black chalky material at the bottom of the pan indicating friction element breakdown.