...its been a long day so humor me here... The problem I have with your question Is that you are saying you are using a T to pick up drainage, which Is big trouble.
Conversesy, I believe You to be referring to a "barret Cleanout" which is a T with one line containing a threaded ( in abs ) cap. If so then do as the other member here said and Just add some Teflon tape to the threads and make sure you tighten it well, Glue Is not the thing to use on threads.
I just wanted to make sure that You wernt trying to use a T In a bullheaded fashion cause it will make your drains Clog up fast.
Bull headed T: Normal flow > T >
illegal use of a t. flow ^