Rebuilt 727 slow to no engage

This is in my D100-440 project. The trans is 1966 and was rebuilt by shop not, me. The guy I got it from has used the shop before and says they do good work but, who knows. Yes I know, go ahead with the tongue lashing. I should have pulled the pan and checked their work. I added a Lokar kickdown cable and shifter which meant I had to loosen the forward/kickdown band nut. (not the adjuster). It was at 2.5 and I did adjust it per the FSM. The engine has to be revved 3k to get engaged in any gear. Sometimes after it engages, it shifts normal between all P-R-D gears at idle. Note: I have not road tested yet. The TC was used and came with the trans. I believe it is stock and big like 11/12 inch. The fluid level is correct and the dip stick measured with the case. Any quick suggestions before I pull trans or the pan and start looking? Also, what are symptoms of a bad TC? Thanks Craig