My Mustang GT has been at a local transmission shop for 2 days having 4.10 gears installed, along with the installation kit. On the first day, they removed the old gears and broke a part (s-spring?). On second day, they spent five hours putting in the new gears and still have not completed the work. They are suppose to be done some time tomorrow. I don't want to rush them because they are trying to do a good job. But, what the heck is taking them so long? Should I be worried?