They charged you $170 to pull the drive, but what is the extra hun for? It takes me about 1/2 hour to pull my drive including the external steering. Them obviously not being familiar with the setup, the drive could be pulled in less than a hour. It doesn't take much more time to reinstall the drive and top off the oil. So $170 to R&R the drive works out to be $85 per hour. That's a bit high, but a feasible shop rate. Now this amount will need be multipied by two for the other side and that's assuming the alignment is good. If the alignment is off, it's anybody's guess what the bill could be.
If you have the tool, this is a job that you can do pretty easily yourself.