Get an 8mill Andrew key. Undo the crank bolt. See if the crank comes off. If so, take it off and see if the bb moves around. If so, And if you have a bb tool. Take off the bb cup. Check for dirt and shizz. Get a crank extractor and remove the other crank. Take the whole bb out and check it over. If its fecked, Replace it, Seeing as its a t-vee im guessing its a square taper bb. Go on selectbikes.com and get a cheapo one off there. Or if you are really lazy take it to you LBS.