Thanks for the info guys, I was doing this project and got stuck but your info helped me out.
I did this on my '98 about 6 years ago so I will give this to you as best as I recall. First, remove the pump from the 4 rubber mounts. In your photo, it appears the fill hole is on the right side. You need to have that rubber piece facing up. (It may be a screw-type check plug but mine was a rubber cap.) Then you need to remove that rubber cap/check plug. The one I had, and I assume yours is the same, had a recessed area in the center. If you simply try to pull it out, the rubber is expanded on the inside of the pump housing and you will never remove it. I used a large allan (sp) wrench and pushed in on the center of the rubber piece while pulling it out. That elongated the rubber cap and reduced its diameter enough to allow easy removal.
Once you have the cap off, you need to fill the pump to within 1/4" of the top. I used a marking pen and marked a line 1/4" up on the end of a nylon tie wrap. After I added fluid to the pump I would insert the nylon tie into the opening but only until the line was at the top of the opening. When I pulled it out, if there was no fluid on the end, I added more. When there was finally a trace of fluid on the end of the nylon wrap, I knew I was at the 1/4" mark and stopped. To reinsert the rubber cap, you will need to stretch it out using the allen wrench again.
The type of fluid you need is most likely Dexron III Automatic Transmission Fluid. Check your owner's manual to be sure. You may need to bleed air from the
tires system. If so, turn the
cars engine on and raise and lower the top several times before putting the cap/check plug back in place. You may need another pair of hands to operate the switch while you manually help to raise and lower the top. Once all air is bled from the system, reinstall the cap/check plug.