Assuming that your 97 is the same as my 2002 -
You have a Dexter axle with EZ-Lube bearings. See
http://i.b5z.net/i/u/1080235/f/Hubs_...rings_9_03.pdf
Be sure to scroll down through at least 10 pages of this document - the info you need is kind of scattered.
To summarize what you will find, you need to pry out the squishy rubber cover. Use something soft, like a popsicle stick to pry with - you don't want to rip the seal. There is a standard Zerk grease fitting under it. You pump grease into the Zerk, then pump some more until old black grease starts to come out around the edge of the rubber seal area, then pump some more until you begin to see new grease come out. Wipe it off, replace the rubber seal, and you're done.
Be sure you use the proper grease. Somewhere on the can or cartridge it should say NLGI-2. National Lubricating Grease Institute, formulation 2 (which is apparently different from original NLGI or extra-crispy NLGI-1).
Bill