Ex Trek employee here. The bearings should need a press to be installed. If you can remove/install them by hand the frame has worn. You need to first try the V2 OS bearings. They are .1mm larger in diameter than the stock 37.0mm bearings. If those are not snug Trek has supplied a kit to it's dealers...well, at least the company owned stores have them...that can be used to machine out a little more carbon which is then replaced w/ a glued in carbon ring that brings the bearing interface back to the correct size. Only use grease when installing the bearings. This has happened on thousands of frames and has been repaired thousands of times at Trek in WI. It's an easy fix for a truly annoying problem...which is why Trek is slowly going back to threaded bottom brackets.