Different problems and the severity of any damage to your transmission will determine the costs. If you are low on fluid and just need a service, you can get out for around $100. More severe problems, like a bad torque converter or broken gear, could mean removal or disassembly of the transmission, which can cost serious money. In some cases, transmission replacement might be a better option than removing, repairing, or replacing. You can find new, used, and rebuilt transmissions for nearly any car, which might be cheaper than a very expensive repair.