What would make fluid come out of the reservoir on a power steering pump I'm a 99 Dodge Ram 1500

Did you over fill it or fill it to the HOT line when it was cold? That will make it over flow for sure. There is a screen in the bottom of most pumps. Yours may be plugged with some sludge.

Second opinion: Reelin68 is right on, agree 100%. But just to clarify, you mean the fluid is coming out the top..where you fill from around the cap? Or somewhere else? And does the power steering seem to work as it should? The screen he is talking about, if plugged up with sludge or any containment, when you turn the steering wheel and the pump wants to draw fluid to pump into the slave cylinder and can't get fluid it will back-up in to the reservoir...therefore creating pressure in the reservoir and the hydraulic fluid needs somewhere to go. But if it's NOT the cap, please come back and let us know where.