Power steering pump replacement

Hi
This is my first posting yes I am a newbie.
What I was hoping is to get some input on replacing my power steering pump. I have a 2001 740il and was told by a repair shop that deals with German cars only. That it was going out. They wanted $550.00 for the part and about $400.00 for the labor. That a bit much for a pump I thought so went to local auto parts store and got one for $116.00 plus $90.00 core. The repair shop list ATF fluid for the pump so I bought some synthetic ATF. Is there anything I need to know going into this?? Thanks in advance for any help. Steve

Not to bad of a job, synth ATF (mobile one) is what I use, take off belt, drop three bolts, remove hoses( these nuts are bad, big air wrench for one of mine, replace all hoses and nuts at same time as they are most are leaking

Thanks going to get this done soon.