While it's inconvenient, there's no reason you can't resolve this yourself.
The transmission fluid pan has a single-use gasket on it, if you just bolt it back on you run the risk of fluid leaks, which could lead to a very expensive problem if you run out of fluid.
While you could bolt it back on and chance it, the better thing to do is to take it off all the way, and do the routine maintenance tasks of a transmission fluid change, which is totally doable at home:
- Replace the transmission fluid filter
- Check for metal in the pan and clean any shavings off of the magnet
- Clean the pan edge and transmission housing edge thoroughly to get all traces of the old seal off
- Put the pan back on with a fresh gasket. You'll need a torque wrench for this part, I think it's 8 foot-pounds
- Refill with fluid, I think it will be Dextron VI for that year but you should check, and you'll probably need about 5 quarts. It's important to do this properly or you could damage your transmission. First with the engine off fill with fluid until it just registers on the dipstick. Then start the engine and run it through the gears, taking your time, holding the brakes and keeping your foot off the accelerator. Check the fluid level and incrementally add small amounts of fluid, running through the gears each time until you get to the right amount on the dipstick. It's very important not to overfill
The filter and gasket should come as a kit, some kits will also have the right kind and amount of transmission fluid as well. A fresh filter and fluid will extend the life of your transmission, so it's good maintenance anyway. There are videos on the web for your make and model, have a look and see if there are any gotchas, it's usually a straightforward process though.
