i have one trim tab that is slow moving.if you go one way{up or down} then try to go the other way it takes a few seconds for it to start moving like it has lost its prime.does it sound like the pump or the ram on the tab?does anyone rebuild either one of these or best just buy a new one? im thinking pump but motor sounds fine

What brand system?

Assuming Merc or K-Planes I have an excellent pump w/solenoids and floor bracket for $150 + shipping ($20-$25)
Freshwater usage, no saltwater

Make certain the fluid reservoir is full and that there is no contamination or water / bubbles in the fluids. While water is not compressible, low fluid levels or aerated fluids will compress.
Not that its relevant, I replaced both solenoids for Port and Starboard pumps for small bucks. This brought both pumps back to perfect working conditions.
For Reference I have twin Merc 496 MAGs. Good luck!