1999q45t pushing p.s.fluid out the cap of the unit the cap is on tight? ps the fluid looks nasty as well

First inspect your cap for damage or parts missing but there's most likely a Blockage. I would tear down the pump looking for debris or causes of blockage. Most systems have, at the relief valve, a way to protect themselves from metallic or hose debris related contamination. The hoses and rack can be purged by cycling left and right. and the hoses can be cleaned and blown out, but it most likely entered at the reservoir. You must remove your pump and then its relief valve. Your return obviously is clear to refill the reservoir as it was(overfilled).overflowing. A seal kit should be inexpensive, but if you cannot fix yours or get it cleaned out and resealed ? Replacing the pump may be the answer.

Steering parts darken the fluid over a period of time and flushing is part of their maintenance. If a system had a cooler added, it would still tend to darken the fluid, but at a slower rate. I suspect fluid was added from a container that had contamination, or a part failure internally will yield a debris that can be looked at to determine its source