The pump was leaking between the body and manifold, I replaced the pump's oil seals and the high pressure seals on the pump. Basically replaced everything except the check valves.

I couldn't find any videos of someone doing this. The pump is a AAA made by Simpson Model Number: 7109378 1016 Rev0

For parts I went to Dewalt's website and looked up my unit by Model Number/Serial Number then searched for the best price on the replacement parts.