I don't know the 1988 but I replaced the one in my 1989 about two weeks ago.
I removed mine from the driver side 'hole' where the tie rod & inner tie rod pass through to the spindle/hub assembly.
I had previously removed the strut & spindle/hub anyway.
I maneuvered mine out by handling it from below and working it through that 'hole'.
You should flush all your old fluid out of the power steering lines & consider adding an in-line filter if you want to increase the life expectancy of your new gear box.
My power steering fluid resevoir has a small screen filter deep inside that filters larger particles. I found this when I removed the resevoir for cleaning. Mine was partially block by crud. This filter is not the one on top that filters new fluid being added.
The Volvo or Ford 'magnefine' type filters are good ones to use... just make sure the flow direction is right. I found two new Ford filters on EBAY for a bargain price. There is a guy there that sells Volvo filters. The 3/8" connectors would probably be the easiest to splice in.