Here's the list of Ruud gas furnaces, GFD, GGD,GRA,GRJ, GRK, GTA, GTJ, AND GTK.
I haven't seen a recently manufactured gas furnace, much less a 90+ unit, that has a standing pilot.
How old is it? Maybe you could call a service company to look at it, as it's kinda hard to diagnose a problem over the internet.