Transmission slipping..
the kickdown linkage is not really a kickdown linkage...it is a throttle pressure linkage...it tell the valve body to increase the line pressure as more load is on the engine/trans...
if it is not install correctly it will ruin a trans...
an improperly adjusted linkage will cause the 2 -3 shift to be late..or not happen...like you have to take your foot off the gas to get it to shift into 3rd.