First of all, I would not pay $400 to repair a 10D. You can easily buy another used one for that price. As far as dSLRs go, that model is ancient so putting a new transmission in that old car is unwise IMO.

Quote Originally Posted by Abiciriderback
...I know this is a vague general question but really wondering if a 10d compared to a 50d body will make that much difference with the same mediocre glass.
This depends on what and how you shoot. You'll find the write speed incredibly faster, the buffer immensely larger, and the FPS blistering hot compared to what you're used to. Are these important to you, I don't know.

Based on personal experience, the 10D produced high quality images up to ISO 200, the 30D up to ISO 400, and the 40D up to ISO 800. For me, each one of these steps was worth each upgrade. So going from a 10D to a 50D would be an IMMENSE step.