I have tried to find a service manual here and failed, I ended up sending my T to N.Y. for repairs.....$190 USD plus postage costs. Sounds like you may have meter probs or shutter probs ? I think the T is worth getting fixed by pro's.
Metro Camera Repairs are the recommended service agents, I should have mine back from them in a few weeks, I asked around here before I sent to them and 2 people who had used them had good things to say.