lmcdill

I just bought a 1992 honda civic lx automatic. Did the normal oil change, new plugs and drained and filled the AT with 3 qts honda atf. I have no idea of previous service intervals. The car has 139,000 miles. It seems that the torque converter does not want to lock out. It took around 30+ miles this morning for it to lock out and then it only stayed for a few miles. Other than that the tranny seems to shift slightly hard. No check engine light on. Where should I start in trying to diagnose this problem? Thanks for all your help.