As long as you can still meter in AE mode you still can meter, then override in manual. Unless your T3 stops working I would not bother with repair or replacement. If you decide on a replacement I would personally stick with the T3N, full information in the viewfinder, mirror lock up, very good build quality. On the other hand, a TC can be had for less money, basic camera, no mirror lock up, only shutter speed shown in the viewfinder, unless you need the more advanced features then a TC or A3 may work for you.