Replacing PS pump-- did search, have 2 questions

[Buicksx3]

I did a search but found only parts for sale.

I need to replace the power steering pump on my 165K mile GN as the bearing is going out, causing a howling sound. My local Autozone can get an Adsco unit for $58 with a $24 core charge, or a $60 Cardone (sp?) unit with a $60 core charge. Why is there such a big difference in core charges? Does one unit come with a pulley, and the other without? Does the OEM PS pulley come right off, or is it pressed onto the pump and require a puller?

Thanks for your help!
Morgan
'87 GN

 

[salvageV6]

My shop used a puller when installing my billet aluminum pulley on the power steering pump.

Can't answer the other ones.

 

[Dwayne]

I recently bought one from GM............it was 48$ and I had to turn my old one in............they come without the pulley so be sure and pull yours off fist before you turn it in......good luck