* Check the vehicle's sticker: Look for a sticker on the driver's side doorjamb or the glove box. This sticker will list the GVWR.
* Consult the owner's manual: The owner's manual will also specify the GVWR.
* Check the Ford website (if possible): Ford's website might have archived information on specifications for older models, but this is not always readily available.
Without knowing the specific trim level and configuration of your 1998 Ford Ranger, I cannot provide the GVWR.