How much would it cost to change a Mercedes G from manual to automatic?

I am sure automatic was your first choice, and now you want a manual. It is best to trade in your current Tc and get manual one. The money you have to spend to have manual transmission installed, it would be wiser to use it towards your down payment. two much and not worth it you should have got a manual from the start yes u can convert from automatic to manual.. however it is not a simple task! you need whole new tranmission, then clutch, fly wheel and so on. it would be lot cheaper to trade in automatic for manual car. to find out the estimate, check your local import performance shop! Theoretically, but it would be very complicated and expensive. You would need (at least) the complete transmission/flywheel/mounts/shifter/shift cables & all brackets/interior console/engine computer from a manual tC. It is possible that you would have to weld or cut to make up differences in mounting locations for manual parts. It would be significantly cheaper, easier and faster to simply purchase a manual tC.